MENG353 - FLUID MECHANICS

CHAPTER 4 FLUID KINEMATICS

ASSOC.PROF.DR.HASAN HACIŞEVKİ

FALL 2017 - 18

EASTERN MEDITERRANEAN UNIVERSITY

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SOURCE: FUNDAMENTALS OF FLUIDMECHANICS

MUNSON,P.GERHART,A.GERHART and HOCHSTEIN

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The basic equations given in section, involving the time derivative of extensive

properties (mass, linear momentum, angular momentum, energy) are required

to analyse any fluid problem. In solid mechanics, we often use a system

representing a quantity of mass of fixed identity. The basic equations are

therefore directly applied to determine the time derivatives of extensive

properties. However, in fluid mechanics it is convenient to work with control

volume, representing a region in space considered for study. The basic

equations based on system approach can not directly applied to control volume

approach.

Fig.4,10 illustrates different types of control volume: fixed control volume,

control volume moving at a constant speed and deforming control volume. In

this section, it is aimed to derive a relationship between the time derivative of

system property and the rate of change of that property within a control volume.

This relationship is expressed by the Reynolds Transport Theorem (RTT) which

establishes a link between the system and control volume approaches.

Before deriving the general form of the RTT, a derivation for one dimensional

fixed control volume is explained in the next section.

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