Sculptor Tutorial #3

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SCULPTOR TUTORIAL III

(level: advanced)

Learn how to create volumes based on the Rapid Volume Creation Table

and learn how to setup and run a simple optimization.

This tutorial is based on the CFD model of a turbo compressor inlet.

Sculptor will be used to deform various stations along the pipe, and also to

ultimately optimize the inlet; the final purpose is to perform an

optimization which reduces the static pressure drop between the inlet and

outlet of the pipe.

Time to complete the Tutorial: 30’

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Contents

1. Rapid Volume Creation Tables ................................................................................................. 3

2. Create a volume for the turbo inlet ......................................................................................... 5

3. Deformation Group Creation ................................................................................................. 10

4. Optimization Preparation (external) ...................................................................................... 15

5. Optimization Preparation (internal) ...................................................................................... 16

Find important things faster:

Basic concept

Remind how to / Tips

In the pictures:

Left Mouse click

Left Mouse double-click

Right Mouse click

Single Operation

Group of Operations

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1. Rapid Volume Creation Tables

In this chapter:

� Introduction to the Rapid Volume Creation Table

This chapter explains the format of the Rapid Volume Creation Table and

demonstrates its usefulness. The user will then use the table to create a

volume around the turbo inlet model.

1. Below is a Rapid Volume Creation Table for the pipe elbow model that can be used with

tutorial one. The basic functions include:

a. Create Volume

b. Modify Volume

i. Translate

ii. Rotate

iii. Scale

c. Insert [Plane Type] Plane

i. Plane types include Average, Planer, Copy

ii. Options include Before, Between, and After

2. With the create volume function, the options are the regions that the created volume

will be centered on.

3. With modify volume functions, the plane column is the column that will be selected, if

only a particular row or column should be selected the R and C columns include the

number of the row or column to be selected on the volume. The value is the number of

units that the selected control points should be deformed. The Coord. column is the

reference coordinate for the function.

Order of operations

Step Function Option Plane R C Value Coord.

1 Create Volume "Wall"

2 Translate su#1 6 Y

3 Rotate tu#2 -90 Z

4 Translate tu#2 -7 Y

5 Translate tu#2 -1 X

6 Insert Average Plane Between tu#1, tu#2

7 Translate tu#2 4 X

8 Translate tu#2 4 Y

9 Translate tu#2 1 -1.6 X

10 Translate tu#2 1 -1.6 Y



13 Translate tu#2 1 1.3 X

14 Translate tu#2 1 0.3 Y

Table 1

Example modify volume commands

Example Insert Plane commands

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15 Translate tu#4 1 1.3 Y

16 Translate tu#4 1 0.3 X



4. The resultant volume will look like the one below. This is a very simple way to

demonstrate and record a volume definition. It is important that the functions be

followed in the exact order that they appear in the table.

Pict 1

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2. Create a volume for the turbo inlet

In this chapter:

� Follow the Rapid Volume Creation Table to create an ASD volume

around a turbo compressor inlet

This chapter provides the Rapid Volume Creation Table for Tutorial III. The

user will follow this table to create a volume around the turbo compressor

inlet.

1. Below is the Rapid Volume Creation Table for this tutorial. Following the table an image

is provided for approximately every fourth step in the table. Make sure to follow the

table step-by-step, paying attention to row and column call-outs on modify volume

functions.

Order of operations

Step Function Option Plane R C Value Coord.

1 Create Volume Section1

2 Translate tu#2 -4 X

3 Translate su#2 -2 Y

4 Insert copy plane after su#2

5 Rotate su#3 -90 Z

6 Translate su#3 2 X


8 Insert planer plane after su#3

9 Rotate su#4 -90 Z


11 Translate su#4 -0.2 X

12 Insert planer plane after su#4

13 Translate su#5 -12.5 Y

14 Insert avg. plane between su#4 & su#5



17 Insert copy plane after su#8


19 Rotate su#9 -90 X

20 Translate su#9 -0.75 Y

21 Translate su#9 2 Z

When creating an ASD volume to be used in an optimization it is important to keep in mind

your ultimate optimization goals and the geometry constraints this will allow you to make

appropriate deformation groups and set the boundaries for the groups properly.

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23 Translate su#9 1 -1.5 Y

24 Translate su#9 1 -1.5 Z

25 Scale st#1 & st#2 1.05 Z

26 Translate tu#1 -0.25 S

27 Translate tu#2 0.25 S



30 Translate su#3 & su#5 1 -1.5 S

31 Translate su#2 & su#6 2 -0.5 Y

After step number 5.

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Final ASD volume configuration.

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3. Deformation Group Creation

In this chapter:

� Setup deformation groups that will be used as analysis variables in

the optimization

� Deform the mesh using control point group and transformation

After the volume is defined the user will setup deformation groups for the

inlet. Images of the volume that is being created will be supplied to ensure

that the user is creating the volume properly.

1. The user will follow the table below to create the custom groups in the “Control Points

Group” dialog box.

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“scaleZ_1” deformations.

“scaleZ_2” deformations

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“transY_1” deformations

“transS_1” deformations

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“scaleXZ_1” deformations

“scaleXZ_2” deformations

2. After the deformation groups have been created, the user can make deformations to the

geometry from the “Deform Geometry by Custom Group” dialog box.

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4. Optimization Preparation (external)

In this chapter:

� Set the sculpt_run_cfd script file

� Setup analysis tool automatic run files

� Begin the optimization

After the volume has been created and the deformation groups have been

formed the user is ready to begin preparation for the optimization. The

following are steps required by Sculptor’s internal optimizer to call

external tools.

1. Sculptor’s optimization process exports a deformed geometry named “sculpt_opt.” with

whatever file extension is required for the current format. After the geometry is

exported Sculptor calls a script named “sculpt_run_cfd” (in Windows this file can be a

batch file or python script). The sculpt_run_cfd script should call the appropriate

analysis tool and read in the geometry named “sculpt_opt” and the associated data file.

The example script below is for ANSYS Fluent. Fluent is called and a journal file named

turbo_inlet.jou is loaded. The –wait flag instructs the batch file to wait until Fluent is

closed to end the batch file.

2. Each analysis tool will have different tools to automatically read a geometry and solve it.

Please refer to your particular solver’s documentation for this information. The journal

file below is used with the Fluent CFD code. This journal file reads in ‘sculpt_opt.cas’ the

deformed geometry output by Sculptor. Solves for up to 1000 iterations. Writes out

integrated static pressures on the inlet and outlet surfaces. Then exits. Sculptor can read

this data into its analysis function dialog that will be discussed in the next chapter.

Because Sculptor does not change the node or element list, a previously converged data set

can be used with the deformed geometry in order to reduce the time to reconverge.

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5. Optimization Preparation (internal)

In this chapter:

� Set the analysis variables and boundaries

� Read in response data from an analysis tool

� Set the optimization parameters

� Run the optimization

After the volume has been created and the deformation groups have been

formed the user is ready to begin preparation for the optimization. The

following are the steps to be taken to prepare for the optimization inside of

Sculptor.

1. Open the “Analysis Variables” dialog box. Left click in the “DV” column to use the

particular group as an analysis variable in the optimization. A green checkmark will

appear in the column after it has been selected. For this optimization select all six groups

to be design variables.

Analysis Variables Dialog box layout.

Custom groups are automatically loaded

into this dialog box

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2. Determine the boundaries for each design variable by manually making the

deformations and checking for any violation of element quality or geometry constraints.

Input the maximum and minimum for each variable in the appropriate columns. The

default boundaries for this optimization are shown below.

3. Now save the volume and groups. The boundaries for each design variable are saved

with the volume file.

4. Open the “Analysis Functions” dialog box to read response data from an analysis tool

into Sculptor. For the initial geometry the response data should be saved in a file with

the same name as the .mdf file, with the extension .res. The format for file should be

two lines of text, the name of the response function and the data type, followed by one

line of data, the response value. This can be repeated for as many lines of response data

as needed. The file “turbo_inlet.res” is shown below. This is the results file which

Sculptor is reading in for the screenshot below. Most analysis tools can format their

output to match this format, if not a third party tool may be required. After the initial

response file has been created, select “Read Results File” to read the data into the

Analysis Functions dialog box.

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Example results file

5. The user can create functions with the function builder tool in the ‘Analysis

Function’ dialog box. For this optimization the user will create a function that is

row B subtracted from row A. This will give the user the pressure drop between

the inlet and outlet. Select ‘Add to List’ to add this function to the response data

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list. Notice the value is automatically calculated. By left clicking in the ‘Obj’

column the user can set the objectives and constraints. Set the objective to

minimize, the arrow pointing down, the function that was just created. The

‘Allowable’ and ‘Indifference’ columns will be automatically calculated for the

optimization parameters. Constraints can also be set by left clicking in the ‘Obj’

column.

6. Set up the optimization parameters by entering the optimize dialog. For this

optimization the default parameters will suffice. For a through treatise on the

optimization parameters for Sculptor’s internal, single objective, gradient based

optimization tool, please see page 54 of the Sculptor manual. After the

parameters have been set select “Optimize” to begin the optimization.

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7. By saving the .mdf file the user will commit the response data to the Sculptor file

system.

8. For the optimization Sculptor will calculate a gradient for each design variable.

The current design variable will be highlighted by a red checkmark. Sculptor will

automatically deform the geometry and export the geometry with the file name

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‘sculpt_opt’. After the geometry has been exported Sculptor will call the

sculpt_run_cfd script. After that script has executed Sculptor will read the

response data from a file named sculpt_opt.res and place the data in the analysis

functions dialog box. After the gradient calls, a line search will be made and all of

the design variables will be deformed together. Generally 3-5 line search calls are

made before the next optimization iteration will commence. Below are a few

screen shots of the optimization being performed with ANSYS Fluent being used

as the analysis tool.

During the second gradient call

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Near the end of the first optimization iteration. Notice the objective has dropped

almost 300 pascals.

The end of the optimization.

Sculptor Tutorial #3

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