Water Tank System Response

download Water Tank System Response

of 23

Transcript of Water Tank System Response

  • 8/13/2019 Water Tank System Response

    1/23

  • 8/13/2019 Water Tank System Response

    2/23

    i

    Abstract

    Two tanks connected in series were studied to determine their responses to step,

    ramp, and on-off changes to inlet flow rate under linear and non-linear discharge control.

    Time constants for the small tank were calculated and compared for a step input yielding

    an average of 15.4 s for filling tank and 21.8 s for emptying tank. The theoretical step

    response for a second order system was compared with the experimental response giving

    percent errors ranging from 10.3% or less at times above 18 s and below 100 s, while

    deviations of up to 8.1% occur above 100 s. Additionally, the experimental on-off

    responses of the single-capacity and two-capacity systems were in agreement with theory,

    except in the case where the tank is empties. Also, it was determined that switching from

    linear to square root discharge profiles caused the time constant of the small tank to

    increase, while the time constant for the large tank decreased.

    It was recommended to use digital control to precisely adjust the on-off valve and

    the flow rate valve in replacement of manual operation. This change could potentially

    improve the precision in ramp input and on-off control responses, thus allowing a more

    accurate calculation of the time constants.

  • 8/13/2019 Water Tank System Response

    3/23

    ii

    Table of Contents

    Abstract ................................................................................................................................ i

    Introduction ..........................................................................................................................1

    Theory ..................................................................................................................................1

    Results and Discussion ........................................................................................................5

    Evaluation of the Time Constants ................................................................................................ 5

    Ramp Input ................................................................................................................................... 7

    On-off Control ............................................................................................................................ 11

    Conclusions and Recommendations ..................................................................................13

    Appendix ............................................................................................................................15

    Original Data .............................................................................................................................. 15

    Sample Calculations ................................................................................................................... 25

  • 8/13/2019 Water Tank System Response

    4/23

    1

    Introduction

    The system under consideration consisted of two tanks in series. Water flowed

    first into tank one, and then out of tank one into a larger tank two. The height of each

    tank was monitored with pressure sensors and transmitted to a computer for data

    collection. A discharge rate proportional to the height in tank one was used to observe

    linear control, and a rate proportional to the square root of height was used for non-linear

    control. Step deviations of gpm in the flow rate as well as ramp inputs with slopes

    of +0.01 gpm/s and 0.02 gpm/s were implemented using a flow valve and rotameter. The

    one and two-tank liquid level responses to these deviations were analyzed. On-off control

    was also applied for the one and two-tank systems and responses were evaluated.

    Theory

    The mass balance for a single tank yields (1), where m is the mass accumulated in

    the tank, is the mass flow rate in and out of the tank.

    (1)

    Dividing both sides of (1) by the density of the fluid and using the definition of

    the volume accumulated in the tank (2) is obtained. The volume of the fluid inside the

    tank is C, the cross-sectional area, multiplied by h, the height of the fluid.

    (2)

    The volumetric flow rate in and out of the tank is represented by q in and q

    respectively. The height of the fluid can be set equal to the product of the outlet

    volumetric flow rate and the outlet resistance, R, yielding (3), where , the time constant

    parameter, equals RC.

  • 8/13/2019 Water Tank System Response

    5/23

    2

    (3)

    For time t = 0, (4) is obtained from (3).

    (4)

    Taking the difference of (4) and (3), deviation variables can be defined as

    , giving (5). For a unit step change in the inletflow rate, is equal to the Heaviside function, H(t).

    (5)

    (6) is obtained by taking the Laplace transform of (5).

    (6)

    For the deviation variable x at t = 0, x(0) = 0. Plugging this into (6) and solving

    for gives (7). (7)

    Laplace inversion of (7) yields (8).

    (8)

    Defining , it can be found that . As time goes toinfinity, y becomes where h ss is the steady state height at infinite timeand h(0) is the height at time zero. With these relationships the height as a function of

    time in response to a step input can be shown as (9).

    (9)

    (9.1) shows the fractional change in height, f, as a function of time.

    (9.1)

  • 8/13/2019 Water Tank System Response

    6/23

    3

    (9.2) is another useful form of (9).

    (9.2)

    For a ramp input where A is the ramp slope, (5) becomes (10).

    (10)(11) is obtained through Laplace transform of (10).

    (11)

    From (11) it follows that

    (12)

    Using y = Rx and performing Laplace inversion produces (13).

    (13)

    As time goes to infinity, a linear form of (13) is obtained and .

    For the two-tank system response, the form of (3) can be used to find equations for each

    tank with time constants and given in (14) and (15). (14)

    (15)

    In (14) and (15) q 1 and q 2 represent the flow rates out of the first and second tanks

    respectively. Defining deviation variables and , (16) and (17) can be obtained.

    (16)

    (17)

  • 8/13/2019 Water Tank System Response

    7/23

    4

    Laplace transform of (16) and (17) yields (18) and (19).

    (18)

    (19)

    With the relation , the height of fluid in the second tank can be found by (20).

    (20)

    For a step input (20) becomes (21) after partial fraction expansion.

    Laplace inversion of (21) gives (22) which is the time domain response of the two-tank

    system.

    [ ] (21)* + (22)

    For a ramp input with slope A, and the two-tank response is seen in

    (23). Laplace inversion gives (24).

    [ ] (23)

    * + (24)For and (22) takes the form of (9) and (24) becomes

    (13). As time goes to infinity, the value of for a ramp response can be

    detrmined. For (24) gives which subsequentlyyields (25). (25)

    can be determined from (25).

  • 8/13/2019 Water Tank System Response

    8/23

    5

    Results and Discussion

    Evaluation of the Time Constants

    The response of a small tank to the sudden change in flow rate from 0.3 gpm to

    0.7 gpm was measured and plotted over time. According to theory, the time constant can

    be found by noting the time where the response is 63.2% of its final value, or 0.632 when

    plotting the fraction of the total change in height. Using this approach and linear

    interpolation, the time constant calculated for filling the tank was 16.1 seconds. Similarly,

    emptying the tank yielded a time constant of 21.7 seconds. An alternative is to use the

    initial value theorem (IVT) for the slope of the response, which says that the initial slope

    is inversely proportional to the time constant of a first-order system. The IVT method

    yielded time constants of 96.2 s for filling and 357.1 s for emptying the small tank.

    Figure 1 shows the response of filling and emptying the small tank after a step input, as

    well as the theoretical solution for filling the tank using an estimated time constant of

    14.6 s.

    Figure 1. Response for filling and emptying the small tank using a step input.

  • 8/13/2019 Water Tank System Response

    9/23

    6

    Another method calls for plotting the log of the fraction of the total change in

    height, and performing a linear regression the slope of the linear fit then corresponds to

    a value of the time constant. This method yielded 14.6 s and 21.8 s as time constants for

    filling and emptying, respectively. Figure 2 shows a semi-log plot of the fraction of the

    total change in height over time, which follows a linear trend for the first 40 seconds. It is

    worth nothing that the time constants yielded by this linear regression method and by

    noting the time at 63.2% completion are similar a relative difference of 9.3% for filling

    and 0.46% for emptying.

    Figure 2. Semi-log plot of the fraction of the total change in height over time.

    The step response of a second-order system was analyzed using the data collected

    from the larger tank. Unlike the step response of the small tank, the initial response of the

    second-order system is much slower. At larger times, the large tank reaches its final

    height faster than predicted by a theoretical step response ( = 30 s, = 60 s).

    Nevertheless, the theoretical model for the second-order system is fairly accurate (within

    10.3% or less from the experimental data) at times above 18 s and below 100 s. Above

  • 8/13/2019 Water Tank System Response

    10/23

    7

    100 seconds, the total change in height for the large tank starts to deviate (up to 8.1%)

    from the theoretical model. Figure 3 shows the step response of the large tank, as well as

    the theoretical step response with = 30 s and = 60 s.

    Figure 3. Step response of the large tank.

    Ramp Input

    For analysis of the system response to a ramp input, two different magnitudes of

    ramp inputs were used. The system was allowed to reach steady state for a flow rate of

    0.3 gpm. The ramp input was manually approximated by continuously adjusting the flow

    rate until a flow of 0.8 gpm was reached. For the slow ramp, the flow rate was increased

    at a rate of 0.1 gpm every 10 seconds, while the flow rate for the fast ramp was increased

    at a rate of 0.2 gpm every 10 seconds. The analysis was performed for both linear

    discharge profile and square root discharge profile. The deviation variable, y is defined as

    (26)

  • 8/13/2019 Water Tank System Response

    11/23

    8

    The time constants for both tanks were determined using the methods outlined in

    the Theory section. As t approaches infinity, the response of the small tank reaches a

    long-time asymptote of the form

    (27)

    This asymptote is a linear function with slope Rb and displaced by time units

    from the origin. In the same manner, the response of the second-order large tank reached

    a long-time asymptote of the form

    ( ) (28)By plotting the linear region of the response and setting y = 0, the time constants

    of the two tanks can be obtained from experimental data. Figure 4 shows the ramp

    response to the slow ramp input with a linear discharge profile. The equations for the fit

    to the linear region of the response are given in the figure.

    Figure 4. The height, h h(0) , as a function of time for the slow ramp with a linear discharge profile.

    y = 0.0953x - 0.9752

    y = 0.0619x - 1.9702

    0

    0.5

    1

    1.5

    2

    2.5

    3

    3.5

    0 10 20 30 40 50 60

    y ( i n

    )

    Time (s)

    Small Tank -Slow RampLarge Tank -Slow RampFit 1

  • 8/13/2019 Water Tank System Response

    12/23

    9

    From equations (27) and (28), it was determined that the time constants for the

    small and large tanks are 10.23 s and 21.60 s, respectively. Figure 5 shows the ramp

    response to the fast ramp input with a linear discharge profile. The equations for the fit to

    the linear region of the response are given in the figure. From the linear regressions, it

    was determined that the time constants for the small and large tanks are 6.79 s and 5.07 s,

    correspondingly.

    Figure 5. The height, h h(0) , as a function of time for the fast ramp with a linear discharge profile.

    Figure 6 shows the ramp response to the slow ramp input with a square

    root discharge profile. Once again, the equations for the fit to the linear region of the

    response are given in the figure. From the linear regressions and equations (27) and (28),

    it was determined that the time constants for the small and large tanks are 12.33 s and

    12.48 s, in that order.

    y = 0.1401x - 0.9514

    y = 0.0127x - 0.1506

    0

    0.2

    0.4

    0.6

    0.8

    1

    1.2

    1.4

    1.6

    1.8

    0 5 10 15 20

    y ( i n

    )

    Time (s)

    Small Tank - Fast RampLarge Tank - Fast

    RampFit Small Tank

    Fit Large Tank

  • 8/13/2019 Water Tank System Response

    13/23

    10

    Figure 6. The height, h h(0) , as a function of time for the slow ramp with a square root dischargeprofile.

    Figure 7 shows the ramp response to the fast ramp input with a square root

    discharge profile. The equations for the fit to the linear region of the response are given

    in the figure. From the linear regressions, it was determined that the time constants for

    the small and large tanks are 5.92 s and 9.02 s, respectively.

    Figure 7. The height, h h(0) , as a function of time for the fast ramp with a square root dischargeprofile.

    y = 0.1116x - 1.3762

    y = 0.0285x - 0.707

    0

    0.5

    1

    1.5

    2

    2.5

    3

    0 5 10 15 20 25 30 35 40

    y ( i n

    )

    Time (s)

    Small Tank -Slow RampLarge Tank -Slow RampFit 1

    Fit 2

    y = 0.14x - 0.8285

    y = 0.0138x - 0.2062

    0

    0.2

    0.4

    0.6

    0.8

    1

    1.2

    1.4

    1.6

    1.8

    0 5 10 15 20

    y ( i n

    )

    Time (s)

    Small Tank -Fast RampLarge Tank -Fast RampFit 1

    Fit 2

  • 8/13/2019 Water Tank System Response

    14/23

    11

    A faster ramp input, corresponding to a larger rate of increase of flow rate, has

    smaller estimated time constants for both tanks. In other words, the system responded

    faster to a ramp input of larger magnitude. Its worth noting that , in general, ramp input

    time constants are smaller than the estimates derived from step inputs.

    On-off Control

    In on-off control analysis, the tanks were first allowed to reach steady state at a

    higher flow rate of 0.5 gpm. The flow rate was then rapidly reduced to 0.3 gpm. The level

    in the tanks were then regulated using a bypass valve on the inlet, which has a very high

    flow rate. A deadband of 2 inches was used when performing the analysis, where the

    bypass valve was opened when the liquid level drops 1 inch below the steady state level

    and closed when the liquid level reaches 1 inch above the steady state level. The system

    response was observed and recorded for single and two-capacity systems. In single

    capacity system analysis, the water level was regulated for the first, smaller tank. In two-

    capacity system analysis, the water level was instead regulated for the second, larger

    tank. Analysis was performed only for a linear discharge profile.

    From Figure 8, it can be seen that the height in the first tank always exceeds the

    upper height limit when filling. This corresponds to the theoretical result obtained in the

    Theory section, which states that the derivative of the height is positive when the height

    hits the upper limit. However, the response when emptying does not match up withtheory. Because there is no input term when emptying, the derivative of the height only

    has a negative discharge term, which means that the lower limit should be exceeded. The

    experimental data shows otherwise.

  • 8/13/2019 Water Tank System Response

    15/23

    12

    Figure 8. On-off control response for a single capacity system with a deadband of 2 inches.

    The upper and lower height limits of the second tank is always exceeded, which is

    in agreement with theory. Figure 9 shows this on a plot of on-off control response over

    time. A large height in the first tank was required to regulate the level in the second tank.

    The values in the vicinity of t = 350 s correspond to a mistake in performing the analysis,

    and should not be used as valid values in the system response.

    Figure 9. On-off control response for a two-capacity system with a deadband of 2 inches.

    -1

    -0.5

    0

    0.5

    1

    1.5

    0 20 40 60 80 100 120 140 160

    y ( i n

    )

    Time (s)

    Tank 1 - SingleCapacity

    -4

    -2

    0

    2

    4

    6

    8

    0 100 200 300 400 500 600 700 800

    y ( i n

    )

    Time (s)

    Tank 1 - TwoCapacity

  • 8/13/2019 Water Tank System Response

    16/23

    13

    The single and two-capacity system are quite different in their responses. The

    single capacity system behaves as a first-order system with multiple step inputs, and the

    second tank displays gradually increasing values of oscillatory behavior. For the two-

    capacity system, there is less control over the height of water in the second tank, and the

    system responds very slowly to any step inputs. This corresponds to a larger time scale,

    where each filling and emptying cycle takes about 150 s, while the single capacity system

    only takes about 25 s.

    Conclusions and Recommendations

    The time constants obtained from the step and ramp inputs agree in the case

    where the ramp input is slow and the discharge profile is set by the square root of the

    height (i.e. flow rate that was increased at a rate of 0.1 gpm every 10 seconds). When

    going from a slow to a fast ramp input, the time constant for the small tank decreases by

    33.6% for the linear discharge profile and by 52.0% for the square root profile. In terms

    of the larger tank, the time constant decreases by 76.5% for the linear discharge profile

    and by 27.7% for the square root profile. Tables 1 and 2 show a summary of all the time

    constants calculated using step and ramp inputs, respectively.

  • 8/13/2019 Water Tank System Response

    17/23

    14

    Table 1. Summary of time constants calculated from the step response of the small tank.

    Method Filling Emptying

    Time at 63.2% completion 16.1 21.7

    IVT for slope 96.2 357.1Linear regression on semi-log plot 14.6 21.8

    Table 2. Summary of time constants for ramp input.

    Linear DischargeInput Tank 1 Tank 2

    Slow Ramp 10.2 21.6Fast Ramp 6.8 5.1

    Square Root DischargeInput Tank 1 Tank 2Slow Ramp 12.3 12.5Fast Ramp 5.9 9.0

    It follows from Table 2 that the time constants for both tanks are a function of the

    discharge profile, as noted in the Theory section. At the same point in time, the level in

    the first tank for a square root discharge profile is higher than the level for a linear

    discharge profile. However, due to the smaller magnitude of the discharge, the level in

    the second tank for a square root discharge profile is smaller than the level for a linear

    discharge profile.

    On-off control for the single capacity system has similar behavior as a first-order

    system with multiple step inputs at a set interval, meanwhile the second tank displays

    oscillatory behavior that increases as a whole over time . In the two-capacity system,

    control over the height of water in the second tank is minimal so the system obtains a

    larger time constant.

  • 8/13/2019 Water Tank System Response

    18/23

    15

    A significant source of error is the presence of bubbles in the inlet lines. This

    means that the actual value of the flow rate is not the value indicated by the rotameter.

    Reading and adjusting the rotameter could also contribute to the error. Another important

    source of error is the manual approximation of a ramp input, which might result in a ramp

    that is not smooth. There was also a slight delay between the time when the level in the

    tanks hit the height limits and the time when the bypass valve was opened or closed in the

    on-off analysis.

    For future studies, its recommended to use automatic valve control in lieu of

    manual operation. This improvement would allow precise control of the ramp input,

    hence the effect a ramp inputs magnitude on time constants would be clearer.

    Appendix

    Original Data

    ElapsedTime

    (s)

    Linear Step Response Linear Ramp Response On-off Response

    Filling Emptying Slow Fast Single-capacity Two-capacityTank 1Level

    Tank 2Level

    Tank 1Level

    Tank 2Level

    Tank 1Level

    Tank 2Level

    Tank 1Level

    Tank 2Level

    Tank 1Level

    Tank 2Level

    Tank 1Level

    Tank 2Level

    0 3.226 0.554 5.276 5.433 2.553 0.66 0.097 2.671 5.723 1.334 3.106 2.686

    0.5 3.228 0.557 5.276 5.429 2.552 0.644 0.098 2.651 5.719 1.357 3.08 2.677

    1 3.217 0.559 5.276 5.431 2.552 0.654 0.101 2.624 5.677 1.384 3.066 2.661

    1.5 3.201 0.573 5.277 5.437 2.553 0.654 0.113 2.586 5.632 1.407 3.052 2.64

    2 3.185 0.583 5.284 5.427 2.552 0.657 0.141 2.541 5.594 1.437 3.046 2.62

    2.5 3.168 0.593 5.283 5.421 2.552 0.66 0.186 2.5 5.553 1.46 3.029 2.611

    3 3.153 0.594 5.283 5.421 2.552 0.66 0.226 2.459 5.513 1.494 3.014 2.6

    3.5 3.139 0.59 5.281 5.414 2.549 0.663 0.269 2.416 5.476 1.521 3.004 2.584

    4 3.126 0.591 5.277 5.417 2.552 0.656 0.316 2.376 5.434 1.566 2.993 2.571

    4.5 3.113 0.601 5.283 5.416 2.552 0.661 0.361 2.333 5.397 1.587 2.983 2.554

    5 3.098 0.599 5.283 5.413 2.552 0.649 0.406 2.294 5.359 1.617 2.972 2.541

    5.5 3.086 0.607 5.283 5.423 2.552 0.644 0.446 2.256 5.331 1.639 2.964 2.524

    6 3.08 0.596 5.279 5.411 2.546 0.644 0.487 2.21 5.297 1.676 2.952 2.51

  • 8/13/2019 Water Tank System Response

    19/23

    16

    6.5 3.063 0.59 5.27 5.407 2.546 0.641 0.531 2.179 5.263 1.704 2.937 2.493

    7 3.051 0.589 5.212 5.41 2.545 0.64 0.571 2.136 5.233 1.717 2.924 2.477

    7.5 3.039 0.586 5.15 5.401 2.548 0.636 0.608 2.096 5.204 1.741 2.916 2.459

    8 3.022 0.59 5.08 5.406 2.55 0.637 0.65 2.056 5.175 1.751 2.906 2.443

    8.5 3.017 0.586 5.017 5.409 2.545 0.651 0.686 2.024 5.143 1.78 2.895 2.427

    9 3.003 0.59 4.952 5.396 2.545 0.649 0.72 1.987 5.117 1.799 2.884 2.414

    9.5 2.999 0.591 4.894 5.389 2.545 0.649 0.759 1.949 5.088 1.82 2.879 2.393

    10 2.986 0.599 4.834 5.387 2.545 0.65 0.792 1.909 5.059 1.829 2.868 2.381

    10.5 2.974 0.587 4.774 5.374 2.545 0.654 0.826 1.874 5.033 1.853 2.855 2.366

    11 2.968 0.591 4.724 5.369 2.545 0.653 0.858 1.84 5.011 1.869 2.852 2.353

    11.5 2.953 0.591 4.67 5.356 2.545 0.653 0.89 1.804 4.986 1.874 2.846 2.329

    12 2.942 0.587 4.611 5.34 2.545 0.646 0.926 1.77 4.963 1.894 2.834 2.314

    12.5 2.931 0.589 4.563 5.336 2.546 0.646 0.954 1.731 4.942 1.921 2.828 2.297

    13 2.924 0.59 4.514 5.337 2.549 0.64 0.989 1.704 4.921 1.909 2.819 2.28

    13.5 2.92 0.584 4.461 5.323 2.545 0.639 1.019 1.667 4.898 1.931 2.815 2.263

    14 2.906 0.586 4.414 5.304 2.545 0.647 1.048 1.639 4.88 1.949 2.814 2.25414.5 2.919 0.584 4.366 5.296 2.545 0.653 1.08 1.599 4.861 1.964 2.821 2.234

    15 2.977 0.581 4.321 5.283 2.552 0.647 1.11 1.569 4.84 1.979 2.834 2.214

    15.5 3.052 0.593 4.277 5.26 2.552 0.636 1.142 1.544 4.825 1.991 2.862 2.196

    16 3.124 0.581 4.233 5.246 2.552 0.646 1.166 1.513 4.808 2.004 2.89 2.181

    16.5 3.186 0.599 4.194 5.23 2.552 0.651 1.197 1.476 4.789 2.019 2.92 2.169

    17 3.261 0.604 4.15 5.214 2.552 0.639 1.228 1.45 4.774 2.024 2.952 2.15

    17.5 3.327 0.589 4.106 5.197 2.552 0.65 1.25 1.416 4.761 2.05 2.986 2.137

    18 3.386 0.597 4.069 5.169 2.552 0.641 1.279 1.38 4.741 2.056 3.022 2.124

    18.5 3.457 0.607 4.029 5.157 2.552 0.641 1.308 1.343 4.721 2.059 3.054 2.107

    19 3.51 0.601 3.993 5.144 2.556 0.631 1.332 1.324 4.71 2.07 3.084 2.0919.5 3.568 0.607 3.959 5.124 2.552 0.631 1.357 1.296 4.694 2.084 3.117 2.074

    20 3.625 0.616 3.92 5.104 2.552 0.643 1.386 1.271 4.679 2.079 3.143 2.064

    20.5 3.68 0.619 3.89 5.084 2.552 0.639 1.41 1.24 4.659 2.096 3.178 2.053

    21 3.735 0.624 3.861 5.067 2.556 0.64 1.436 1.211 4.65 2.109 3.199 2.039

    21.5 3.783 0.616 3.829 5.049 2.552 0.64 1.458 1.184 4.634 2.111 3.234 2.029

    22 3.836 0.619 3.799 5.033 2.552 0.631 1.48 1.15 4.623 2.129 3.259 2.017

    22.5 3.879 0.633 3.767 5.004 2.552 0.63 1.502 1.124 4.611 2.141 3.287 1.997

    23 3.927 0.624 3.738 4.99 2.552 0.634 1.526 1.1 4.596 2.153 3.317 1.987

    23.5 3.974 0.634 3.706 4.967 2.552 0.651 1.548 1.076 4.589 2.159 3.342 1.981

    24 4.022 0.639 3.681 4.943 2.557 0.631 1.57 1.047 4.572 2.154 3.374 1.969

    24.5 4.066 0.646 3.655 4.924 2.559 0.634 1.592 1.024 4.564 2.164 3.393 1.959

    25 4.109 0.667 3.626 4.897 2.559 0.627 1.612 0.997 4.554 2.177 3.417 1.943

    25.5 4.145 0.661 3.6 4.88 2.559 0.627 1.637 0.971 4.542 2.179 3.436 1.943

    26 4.189 0.674 3.574 4.856 2.559 0.629 1.657 0.947 4.535 2.181 3.461 1.934

    26.5 4.23 0.686 3.548 4.83 2.563 0.62 1.677 0.931 4.523 2.187 3.48 1.923

    27 4.266 0.699 3.524 4.813 2.566 0.626 1.694 0.92 4.51 2.199 3.503 1.916

    27.5 4.302 0.704 3.503 4.783 2.566 0.636 1.712 0.88 4.502 2.211 3.526 1.907

  • 8/13/2019 Water Tank System Response

    20/23

    17

    28 4.345 0.711 3.479 4.75 2.566 0.633 1.731 0.859 4.495 2.207 3.546 1.897

    28.5 4.382 0.724 3.454 4.741 2.566 0.641 1.749 0.843 4.484 2.211 3.564 1.889

    29 4.412 0.734 3.432 4.724 2.567 0.626 1.767 0.826 4.474 2.224 3.585 1.881

    29.5 4.446 0.744 3.41 4.693 2.567 0.627 1.781 0.8 4.465 2.22 3.607 1.874

    30 4.476 0.757 3.39 4.669 2.566 0.629 1.797 0.78 4.459 2.23 3.621 1.87

    30.5 4.51 0.769 3.368 4.623 2.566 0.629 1.814 0.76 4.452 2.241 3.637 1.864

    31 4.548 0.78 3.348 4.611 2.566 0.614 1.832 0.739 4.448 2.251 3.657 1.859

    31.5 4.579 0.799 3.332 4.586 2.564 0.63 1.846 0.72 4.436 2.244 3.677 1.851

    32 4.604 0.816 3.312 4.56 2.564 0.629 1.866 0.703 4.434 2.253 3.691 1.851

    32.5 4.632 0.824 3.297 4.539 2.566 0.627 1.883 0.683 4.428 2.267 3.709 1.844

    33 4.659 0.834 3.279 4.507 2.56 0.637 1.892 0.66 4.426 2.264 3.724 1.843

    33.5 4.687 0.85 3.259 4.48 2.566 0.634 1.91 0.64 4.419 2.276 3.741 1.833

    34 4.712 0.871 3.243 4.46 2.566 0.647 1.926 0.621 4.41 2.286 3.749 1.829

    34.5 4.731 0.887 3.228 4.427 2.566 0.629 1.937 0.611 4.407 2.283 3.766 1.83

    35 4.753 0.911 3.21 4.407 2.566 0.629 1.953 0.597 4.399 2.28 3.782 1.821

    35.5 4.777 0.924 3.192 4.377 2.577 0.636 1.964 0.563 4.39 2.297 3.793 1.82336 4.803 0.947 3.178 4.354 2.59 0.634 1.978 0.561 4.383 2.293 3.811 1.821

    36.5 4.826 0.961 3.161 4.319 2.596 0.64 1.993 0.546 4.378 2.293 3.821 1.813

    37 4.851 0.974 3.149 4.304 2.6 0.637 2.006 0.533 4.377 2.297 3.836 1.807

    37.5 4.868 0.996 3.141 4.281 2.611 0.636 2.018 0.524 4.37 2.311 3.846 1.804

    38 4.891 1.017 3.13 4.253 2.625 0.643 2.033 0.507 4.37 2.307 3.858 1.807

    38.5 4.913 1.036 3.117 4.226 2.641 0.64 2.054 0.51 4.361 2.31 3.874 1.797

    39 4.934 1.057 3.102 4.191 2.662 0.636 2.065 0.504 4.359 2.309 3.886 1.797

    39.5 4.945 1.073 3.086 4.186 2.677 0.634 2.074 0.507 4.359 2.321 3.899 1.799

    40 4.964 1.099 3.074 4.154 2.691 0.63 2.083 0.504 4.352 2.333 3.91 1.793

    40.5 4.983 1.116 3.062 4.127 2.702 0.636 2.099 0.501 4.341 2.329 3.916 1.79341 5 1.136 3.048 4.103 2.723 0.626 2.112 0.513 4.345 2.337 3.928 1.794

    41.5 5.01 1.151 3.036 4.071 2.745 0.629 2.121 0.507 4.337 2.334 3.945 1.796

    42 5.032 1.173 3.023 4.049 2.774 0.627 2.137 0.504 4.331 2.336 3.952 1.789

    42.5 5.05 1.194 3.008 4.029 2.79 0.63 2.145 0.506 4.328 2.344 3.956 1.789

    43 5.057 1.221 3 3.996 2.811 0.617 2.153 0.51 4.321 2.347 3.968 1.783

    43.5 5.07 1.239 2.992 3.98 2.837 0.631 2.163 0.5 4.324 2.353 3.975 1.79

    44 5.09 1.263 2.983 3.959 2.862 0.631 2.177 0.506 4.324 2.359 3.989 1.794

    44.5 5.101 1.279 2.97 3.937 2.883 0.651 2.188 0.5 4.319 2.351 3.997 1.787

    45 5.108 1.313 2.957 3.914 2.912 0.643 2.196 0.513 4.312 2.361 4.001 1.783

    45.5 5.128 1.331 2.945 3.887 2.937 0.649 2.204 0.513 4.309 2.366 4.007 1.786

    46 5.139 1.353 2.932 3.85 2.959 0.63 2.214 0.511 4.305 2.364 4.015 1.786

    46.5 5.15 1.377 2.926 3.834 2.99 0.633 2.222 0.514 4.303 2.374 4.022 1.787

    47 5.163 1.403 2.919 3.817 3.023 0.644 2.233 0.51 4.298 2.379 4.032 1.787

    47.5 5.171 1.414 2.91 3.793 3.052 0.633 2.248 0.514 4.299 2.374 4.039 1.779

    48 5.182 1.444 2.902 3.763 3.087 0.64 2.248 0.506 4.297 2.374 4.05 1.781

    48.5 5.194 1.469 2.89 3.734 3.113 0.653 2.254 0.504 4.29 2.376 4.057 1.781

    49 5.207 1.491 2.88 3.717 3.139 0.644 2.263 0.513 4.29 2.379 4.063 1.781

  • 8/13/2019 Water Tank System Response

    21/23

    18

    49.5 5.221 1.523 2.872 3.691 3.175 0.65 2.27 0.504 4.283 2.38 4.069 1.781

    50 5.23 1.547 2.865 3.667 3.208 0.656 2.281 0.51 4.28 2.383 4.076 1.793

    50.5 5.236 1.571 2.858 3.644 3.243 0.65 2.294 0.513 4.276 2.386 4.083 1.787

    51 5.239 1.596 2.851 3.624 3.277 0.671 2.297 0.504 4.276 2.384 4.083 1.786

    51.5 5.248 1.627 2.841 3.606 3.316 0.66 2.308 0.514 4.273 2.38 4.088 1.794

    52 5.258 1.649 2.834 3.586 3.345 0.666 2.314 0.509 4.272 2.384 4.097 1.789

    52.5 5.268 1.681 2.823 3.559 3.386 0.673 2.32 0.514 4.269 2.389 4.103 1.789

    53 5.277 1.699 2.815 3.524 3.432 0.679 2.33 0.511 4.262 2.384 4.106 1.787

    53.5 5.284 1.724 2.808 3.503 3.468 0.673 2.334 0.507 4.262 2.39 4.114 1.793

    54 5.287 1.759 2.804 3.49 3.514 0.667 2.341 0.516 4.259 2.389 4.12 1.794

    54.5 5.297 1.783 2.8 3.467 3.56 0.671 2.345 0.511 4.251 2.387 4.124 1.8

    55 5.303 1.809 2.793 3.437 3.608 0.673 2.352 0.516 4.251 2.39 4.126 1.803

    55.5 5.31 1.834 2.786 3.423 3.648 0.671 2.359 0.516 4.247 2.397 4.131 1.806

    56 5.312 1.863 2.778 3.403 3.695 0.68 2.363 0.504 4.241 2.4 4.138 1.806

    56.5 5.314 1.879 2.771 3.381 3.743 0.677 2.368 0.514 4.241 2.391 4.143 1.807

    57 5.319 1.904 2.766 3.363 3.778 0.683 2.372 0.514 4.239 2.4 4.145 1.81357.5 5.328 1.941 2.76 3.331 3.822 0.684 2.379 0.523 4.234 2.399 4.146 1.817

    58 5.332 1.969 2.75 3.31 3.872 0.694 2.386 0.513 4.233 2.396 4.152 1.82

    58.5 5.337 1.993 2.743 3.294 3.924 0.697 2.393 0.516 4.228 2.39 4.159 1.82

    59 5.338 2.001 2.738 3.273 3.959 0.711 2.399 0.511 4.226 2.396 4.159 1.821

    59.5 5.301 2.026 2.734 3.246 4.003 0.719 2.4 0.516 4.222 2.409 4.166 1.819

    60 5.32 2.03 2.723 3.226 4.057 0.717 2.406 0.504 4.222 2.404 4.166 1.82

    60.5 5.302 2.044 2.723 3.211 4.098 0.737 2.41 0.514 4.221 2.404 4.171 1.819

    61 5.326 2.07 2.717 3.19 4.148 0.734 2.407 0.506 4.221 2.406 4.174 1.821

    61.5 5.314 2.07 2.712 3.169 4.208 0.744 2.414 0.52 4.218 2.414 4.177 1.819

    62 5.337 2.093 2.699 3.146 4.259 0.75 2.419 0.523 4.212 2.411 4.186 1.82462.5 5.328 2.12 2.695 3.12 4.305 0.769 2.421 0.521 4.214 2.399 4.186 1.831

    63 5.354 2.156 2.69 3.091 4.349 0.783 2.425 0.517 4.208 2.404 4.192 1.83

    63.5 5.337 2.16 2.69 3.069 4.397 0.799 2.428 0.51 4.21 2.41 4.192 1.829

    64 5.356 2.173 2.687 3.053 4.441 0.817 2.432 0.509 4.208 2.411 4.203 1.84

    64.5 5.354 2.19 2.676 3.027 4.498 0.821 2.436 0.513 4.207 2.411 4.204 1.846

    65 5.364 2.213 2.665 3.009 4.542 0.821 2.441 0.517 4.206 2.41 4.207 1.854

    65.5 5.354 2.23 2.662 2.999 4.592 0.841 2.448 0.516 4.204 2.41 4.207 1.846

    66 5.367 2.26 2.662 2.97 4.64 0.85 2.451 0.504 4.201 2.413 4.207 1.851

    66.5 5.366 2.256 2.661 2.956 4.699 0.873 2.451 0.511 4.2 2.409 4.207 1.856

    67 5.371 2.276 2.652 2.937 4.75 0.884 2.455 0.51 4.2 2.407 4.211 1.854

    67.5 5.372 2.293 2.643 2.91 4.79 0.904 2.461 0.523 4.199 2.409 4.214 1.856

    68 5.383 2.323 2.641 2.89 4.847 0.926 2.462 0.509 4.197 2.404 4.214 1.863

    68.5 5.372 2.34 2.641 2.871 4.886 0.943 2.472 0.516 4.167 2.407 4.214 1.86

    69 5.386 2.337 2.641 2.857 4.927 0.969 2.473 0.51 4.123 2.41 4.218 1.874

    69.5 5.378 2.369 2.637 2.834 4.977 0.989 2.476 0.523 4.081 2.407 4.225 1.863

    70 5.39 2.379 2.634 2.809 5.019 0.994 2.476 0.523 4.048 2.406 4.222 1.876

    70.5 5.381 2.406 2.63 2.79 5.061 1.014 2.481 0.523 4.012 2.399 4.228 1.874

  • 8/13/2019 Water Tank System Response

    22/23

    19

    71 5.39 2.414 2.626 2.769 5.099 1.031 2.483 0.523 3.974 2.4 4.228 1.881

    71.5 5.381 2.431 2.625 2.743 5.145 1.056 2.487 0.514 3.95 2.399 4.23 1.883

    72 5.406 2.441 2.628 2.726 5.188 1.079 2.49 0.524 3.91 2.393 4.234 1.893

    72.5 5.388 2.473 2.619 2.703 5.229 1.099 2.494 0.524 3.877 2.389 4.234 1.89

    73 5.397 2.47 2.618 2.689 5.263 1.121 2.497 0.514 3.844 2.39 4.241 1.887

    73.5 5.382 2.49 2.61 2.673 5.291 1.144 2.497 0.523 3.817 2.377 4.24 1.889

    74 5.399 2.52 2.614 2.651 5.324 1.173 2.503 0.516 3.786 2.38 4.24 1.887

    74.5 5.408 2.543 2.611 2.623 5.357 1.196 2.503 0.52 3.756 2.37 4.241 1.893

    75 5.397 2.55 2.603 2.61 5.39 1.227 2.509 0.509 3.726 2.364 4.241 1.899

    75.5 5.414 2.566 2.599 2.586 5.422 1.256 2.51 0.504 3.697 2.354 4.246 1.906

    76 5.399 2.576 2.599 2.564 5.45 1.276 2.51 0.517 3.665 2.351 4.243 1.909

    76.5 5.426 2.591 2.597 2.546 5.477 1.304 2.514 0.507 3.637 2.346 4.248 1.913

    77 5.41 2.609 2.593 2.521 5.508 1.337 2.517 0.506 3.614 2.344 4.248 1.921

    77.5 5.418 2.626 2.586 2.496 5.531 1.369 2.517 0.511 3.588 2.339 4.248 1.923

    78 5.415 2.646 2.582 2.49 5.561 1.394 2.517 0.513 3.563 2.326 4.243 1.916

    78.5 5.423 2.657 2.586 2.467 5.575 1.417 2.521 0.494 3.546 2.319 4.24 1.9279 5.428 2.676 2.586 2.45 5.606 1.441 2.524 0.507 3.524 2.309 4.248 1.92

    79.5 5.425 2.677 2.579 2.431 5.632 1.477 2.527 0.516 3.499 2.304 4.255 1.92

    80 5.426 2.699 2.579 2.414 5.651 1.51 2.531 0.507 3.473 2.294 4.255 1.926

    80.5 5.415 2.713 2.578 2.393 5.676 1.543 2.531 0.5 3.535 2.286 4.244 1.931

    81 5.432 2.72 2.572 2.373 5.694 1.576 2.531 0.509 4.211 2.277 4.212 1.939

    81.5 5.422 2.737 2.572 2.354 5.719 1.607 2.535 0.503 5.043 2.28 4.179 1.937

    82 5.43 2.739 2.572 2.324 5.735 1.636 2.538 0.504 5.583 2.286 4.145 1.934

    82.5 5.425 2.767 2.566 2.309 5.753 1.674 2.538 0.501 5.55 2.3 4.103 1.939

    83 5.433 2.779 2.566 2.29 5.766 1.7 2.545 0.507 5.498 2.31 4.066 1.937

    83.5 5.43 2.797 2.568 2.274 5.79 1.739 2.542 0.509 5.433 2.34 4.034 1.93984 5.447 2.806 2.566 2.256 5.804 1.773 2.543 0.501 5.36 2.354 3.994 1.939

    84.5 5.44 2.823 2.56 2.233 5.821 1.811 2.546 0.497 5.292 2.376 3.957 1.936

    85 5.44 2.834 2.559 2.219 5.833 1.846 2.552 0.506 5.215 2.393 3.921 1.937

    85.5 5.437 2.853 2.559 2.196 5.848 1.883 2.552 0.503 5.146 2.414 3.887 1.939

    86 5.437 2.864 2.559 2.173 5.869 1.913 2.553 0.513 5.088 2.42 3.852 1.94

    86.5 5.447 2.889 2.554 2.154 2.559 0.513 5.017 2.429 3.822 1.933

    87 5.436 2.906 2.556 2.134 2.559 0.516 4.949 2.446 3.792 1.94

    87.5 5.439 2.921 2.556 2.109 2.559 0.516 4.894 2.46 3.763 1.933

    88 5.421 2.939 2.554 2.1 2.561 0.507 4.833 2.473 3.731 1.926

    88.5 5.433 2.947 2.549 2.087 2.561 0.497 4.772 2.476 3.702 1.923

    89 5.43 2.959 2.545 2.066 2.564 0.509 4.717 2.484 3.673 1.914

    89.5 5.432 2.969 2.542 2.04 2.566 0.5 4.665 2.494 3.648 1.907

    90 5.415 2.987 2.545 2.024 2.568 0.521 4.608 2.497 3.625 1.906

    90.5 5.433 3 2.545 2.009 2.566 0.506 4.553 2.504 3.594 1.9

    91 5.434 3.017 2.542 1.991 2.572 0.501 4.508 2.509 3.571 1.89

    91.5 5.417 3.027 2.532 1.973 2.572 0.511 4.459 2.513 3.549 1.88

    92 5.443 3.044 2.531 1.941 2.578 0.506 4.411 2.519 3.523 1.879

  • 8/13/2019 Water Tank System Response

    23/23

    92.5 5.417 3.074 2.534 1.927 2.579 0.504 4.366 2.516 3.498 1.877

    93 5.433 3.091 2.532 1.914 2.586 0.509 4.319 2.52 3.476 1.867

    93.5 5.421 3.096 2.532 1.897 2.592 0.499 4.277 2.529 3.455 1.857

    94 5.426 3.109 2.535 1.877 2.612 0.499 4.228 2.529 3.432 1.841

    94.5 5.421 3.139 2.531 1.854 2.632 0.499 4.189 2.536 3.412 1.831

    95 5.426 3.156 2.526 1.843 2.658 0.491 4.145 2.527 3.39 1.824

    95.5 5.43 3.156 2.528 1.826 2.681 0.497 4.103 2.533 3.367 1.821

    96 5.426 3.187 2.527 1.807 2.708 0.496 4.066 2.534 3.35 1.809

    96.5 5.423 3.2 2.524 1.791 2.734 0.494 4.028 2.529 3.332 1.8

    97 5.417 3.217 2.524 1.773 2.761 0.499 3.99 2.523 3.312 1.796

    97.5 5.425 3.224 2.524 1.757 2.797 0.503 3.952 2.526 3.292 1.787

    98 5.419 3.24 2.523 1.734 2.826 0.509 3.921 2.519 3.274 1.781

    98.5 5.422 3.249 2.524 1.716 2.862 0.497 3.89 2.507 3.261 1.767

    99 5.417 3.273 2.517 1.699 2.903 0.506 3.858 2.513 3.24 1.761

    99.5 5.43 3.276 2.52 1.679 2.935 0.509 3.823 2.507 3.222 1.747

    100 5.429 3.294 2.517 1.664 2.967 0.503 3.793 2.501 3.208 1.733100.5 5.408 3.309 2.517 1.649 3.006 0.521 3.764 2.499 3.189 1.727

    101 5.426 3.331 2.517 1.639 3.054 0.52 3.732 2.491 3.17 1.714

    101.5 5.399 3.351 2.517 1.616 3.108 0.529 3.708 2.48 3.159 1.703

    102 5.418 3.357 2.517 1.596 3.154 0.524 3.68 2.481 3.143 1.694

    102.5 5.397 3.381 2.51 1.581 3.203 0.526 3.657 2.474 3.132 1.683

    103 5.415 3.394 2.51 1.563 3.252 0.529 3.629 2.464 3.117 1.674

    103.5 5.41 3.414 2.51 1.549 3.31 0.521 3.604 2.463 3.101 1.656

    104 5.417 3.427 2.509 1.536 3.361 0.524 3.582 2.459 3.087 1.646

    104.5 5.417 3.444 2.51 1.519 3.422 0.527 3.553 2.443 3.076 1.637

    105 5.41 3.456 2.513 1.5 3.483 0.539 3.53 2.441 3.057 1.626105.5 5.411 3.47 2.51 1.484 3.546 0.521 3.508 2.43 3.046 1.611

    106 5.418 3.48 2.51 1.466 3.606 0.537 3.484 2.424 3.029 1.597

    106.5 5.406 3.493 2.51 1.451 3.67 0.536 3.622 2.417 3.015 1.591

    107 5.418 3.516 2.51 1.434 3.732 0.549 4.219 2.411 3.003 1.577

    107.5 5.423 3.527 2.51 1.417 3.797 0.547 5.105 2.4 2.99 1.569

    108 5.432 3.543 2.512 1.406 3.865 0.561 5.575 2.413 2.977 1.556

    108.5 5.407 3.551 2.513 1.384 3.937 0.56 5.545 2.431 2.961 1.54

    109 5.422 3.576 2.51 1.366 4.015 0.567 5.492 2.447 2.945 1.533

    109.5 5.399 3.581 2.51 1.351 4.079 0.577 5.426 2.473 2.93 1.516

    110 5.419 3.596 2.509 1.34 4.148 0.589 5.349 2.477 2.921 1.504

    110.5 5.4 3.604 2.508 1.323 5.283 2.501 2.914 1.49

    111 5.412 3.629 2.505 1.311 5.211 2.517 2.903 1.473

    111.5 5.406 3.636 2.503 1.299 5.141 2.53 2.89 1.466

    112 5.421 3.657 2.503 1.284 5.083 2.547 2.874 1.459

    112.5 5.412 3.664 2.503 1.267 5.01 2.55 2.863 1.437

    113 5.421 3.677 2.499 1.251 4.939 2.571 2.854 1.42