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Mr. Rishabh Kumar

How to carry out Shape optimization of Axisymmetric body for minimum drag

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Hi Everyone, I'm new to the CAESES. Currently i'm using Star CCM+ to find the drag resistance of a axisymmetric body.

 

 

The offsets of the body is derived by using parametric equations along the length of the body using excel. I want to vary certain parameters(like position of max diameter along the length) to get different shapes and then find the drag. In the end I have to arrive at a shape having minimum resistance and maximum volume. 

 

the workflow is like:

 

change the parameters in excel, get the offsets from the excel file and use them to make a geometry and do an analysis in starccm+ to get the drag.

 

Can CAESES help me with this optimization problem?

please do let me know how : )

 

Can somebody please guide me how to do this ?

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Hi Rishabh,

 

Sure, this is something where CAESES can support you. Sounds interesting. There are 2 options that come to my mind.

 

  • OPTION 1: Use the COM interface possibilities of CAESES to change the parameters in Excel. Write out the offset data and import it into CAESES automatically by writing a little feature for it. Here is an example for an export, importing data is similar.
  • OPTION 2: Transfer the parametric equations into CAESES (set them up in feature definitions, these allow you to define any kinds of functions and expressions etc) and do the entire job in CAESES. I.e. Excel is no longer part of your workflow. Everything is in CAESES. Can be a convenient option, one GUI for your theoretical stuff, the geometry modeling, the optimization setup and the STAR-CCM+ connection.

 

What kind of geometry do you want to generate, do you have a picture?

 

In both workflows, the changes can be done by the inbuilt design engines (optimization strategies) of CAESES. STAR-CCM+ can also be easily coupled to CAESES, and fully automated.

 

Cheers

Joerg

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Hi Rishabh,

 

Sure, this is something where CAESES can support you. Sounds interesting. There are 2 options that come to my mind.

 

  • OPTION 1: Use the COM interface possibilities of CAESES to change the parameters in Excel. Write out the offset data and import it into CAESES automatically by writing a little feature for it. Here is an example for an export, importing data is similar.
  • OPTION 2: Transfer the parametric equations into CAESES (set them up in feature definitions, these allow you to define any kinds of functions and expressions etc) and do the entire job in CAESES. I.e. Excel is no longer part of your workflow. Everything is in CAESES. Can be a convenient option, one GUI for your theoretical stuff, the geometry modeling, the optimization setup and the STAR-CCM+ connection.

 

What kind of geometry do you want to generate, do you have a picture?

 

In both workflows, the changes can be done by the inbuilt design engines (optimization strategies) of CAESES. STAR-CCM+ can also be easily coupled to CAESES, and fully automated.

 

Cheers

Joerg

 

The profile of the body is made of spline and the fluid domain is made out of lines. It's extruded to make a 2D fluid domain in Star CCM+ itself.( I attached the images) 

 

What I want is to modify the profile by changing the parameters and run the stimulation each time to get the drag coefficient. I hope CAESES will help me doing this!!!

 

 

 

Thanks for your time really, I really appreciate your help  :) 

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post-927-0-56667300-1509802038_thumb.png

post-927-0-90820500-1509802039_thumb.png

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Hi Rishabh,

 

Sure, this looks like a perfect job for CAESES. Which option do you have in mind (see my last post)? Can you transfer the stuff from Excel easily i.e. are the equations rather easy to define again in CAESES? It would make the entire process easier, I think.

 

Do you have experience with automating STAR-CCM+ (using it in batch mode along with Java macros)?

 

Cheers

Joerg

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Hi, pal!

 

 

sorry for super late response! I figured out the geometry part myself. Now I have like 50 offsets in .CSV format in a folder. I want to calculate drag of each of them by setting up a simulation case in Star CCM+

 

Can CAESES help me in automating this ?

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Hi Rishabh,

 

A possible solution could be:

  1. Write a feature that imports your csv data for a single design for a given index (e.g. design index d=123).
  2. Connect STAR-CCM+ to CAESES
  3. Run a design engine (ensemble investigation) with a series for the design indices: 0,1..index_max)

 

This creates your N designs along with all the STAR-CCM+ results. Fully automated.

 

Cheers

Joerg

 

Related post: Coupling CAESES with Star-CCM+

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