8 Replies Latest reply on Oct 19, 2012 1:38 PM by Alex Kramer

    I want to run a parametric flow study, not optimization. Is it possible?

    Alex Kramer

      I just started using Solidworks Flow Simulation 2012. The example presented in the training manual for a parametric study is really an optimization problem. It is looking for the value of a dimension which satisfies a pressure force condition.

       

      I want to know the flow vs inlet pressure curve for a channel. I can make a table in which each row represents the pressure at the inlet boundary condition and the program should run a simulation for each row of the table and return the mass flow through the channel in a table. Of course I could do this manually by making a new configuration for each row in the table and do a batch run, but what if I want 50 rows in the table and I want to run it on 30 different gases?

       

      Can Flow Simulation run a simulation multiple times with one parameter varied, and report the results in a table? This is a feature that people who design products would really use a lot.

        • Re: I want to to a parametric flow study, not optimization. Is it possible?
          Jared Conway

          Hi Alex, have you checked out 2013? That is a new function for 2013.

           

          In previous versions you need to leverage the clone project tool to create copies of the configuration/project, make the modification then use the batch run tool to run all the configurations/projects. From there unfortuantely it is a manual process to gather the information from each configuration. You might be able to leverage the batch results tool to get the goals output into files without touching each configuration but you'd have to get fancy with excel to pull together the data in another excel spreadsheet automatically.

          • Re: I want to run a parametric flow study, not optimization. Is it possible?
            Bill McEachern

            There is a single variable goal seek option designed for exactly what you are trying to under solve-> parametric study. there is a training example as well that you can download from the solidworks web site. You don't get any explanation but you can download the file with results and it will have the set up.

              • Re: I want to run a parametric flow study, not optimization. Is it possible?
                Alex Kramer

                Hi Bill,

                I took the training course and I have the manual. That example solves for the piston position which will satisfy the force criteria. So that method could tell me how much inlet pressure I need to provide a specified flow. It will run a few iterations until it finds that and then stops. What I want is to know the flow for each and every inlet pressure boundary condition I specify so I can plot the flow vs inlet pressure curve. When I get a chance I will try the macro function to do this.

                  • Re: I want to run a parametric flow study, not optimization. Is it possible?
                    Bill McEachern

                    It might work, I have to admit I did not read your original post all that carefully. You would need to make sure that the goal you set never gets reached to ensure it spans the whole range of interest. The other apporach is, as mentioned previously, to clone the project a bunch of times and change the inlet pressure to whatever resolution you need over the range of interest and then use a batch run to send them all off. Then collect the data and plot the curve. In 2013 there is supposedly an option to automate this and collect all the data for you. I haven't given it a whirl yet so I can't adive on how it works. Good luck.

                    • Re: I want to run a parametric flow study, not optimization. Is it possible?
                      Jared Conway

                      Yep, you're right Alex in your case if you want to graph value vs parameter, you'll need to run through all the iterations or check out 2013.

                       

                      As for making your own parameter sweep, the Flow Simulation API is open but I think limited. I think here at Hawk Ridge our API team tried writing a parameter sweep for flow and ran into some issues. That being said, there may have been changes in 2012 that would help. The documentation on the API is located in

                      C:\Program Files\SolidWorks Corp 2013\SolidWorks Flow Simulation\lang\english and always be sure to double check the solidworks KB at customerportal.solidworks.com if you have additional questions.

                       

                      Overal though, I wouldn't discount what Bill is saying regarding the parametric study (optimization in 2013). It is a very powerful tool if you have a specific parameter that you're shooting for. If you have a specific interest, you might want to start there and then build your curve  afterwards.

                       

                      Good luck!

                      • Re: I want to run a parametric flow study, not optimization. Is it possible?
                        Bill McEachern

                        The other thing is that it is very likely (assuming you don't run across an R'number regime change) that the realtionship will be strongly parabolic so you probably don't need a lot of points......

                          • Re: I want to run a parametric flow study, not optimization. Is it possible?
                            Alex Kramer

                            Great suggestions Bill and Jared, Thank You.

                             

                            The reason I want so many points is we have been characterizing flow channels experimentally. We recently bought Flow Simulation and I need to prove the simulation matches the experiment results before we can rely on it to predict new flow channel designs. But yes, I can probably make due with less points and I certainly will if it is to be done manually. We will update to 2013 but we have one user running an older OS so that limits are ability to upgrade at the moment.