Learning Forum

[DanielOliveira]

I would like to simulate an elastic membrane valve, but instead of simulating the FSI to obtain its deformation, I wanted to use a static boundary/surface that is totally opened or totally closed over time depending on the direction of the total pressure over its area.nIs it possible?.AppreciatenBest Regardsnn

[YasserSelima]

Use Execute commands. This enables you to change the boundary during simulation ... Look in the manual for details.nnOr use events in dynamic mesh.n

[DanielOliveira]

Appreciate your help. What I'm looking for is to make that region/boundary 100% or 0% permeable, depending on the pressure direction at the entrance. Then I can avoid any dynamic mesh, saving computational time. Do you know if it s possible?.Thanksn

[DanielOliveira]

Well, after some google, I found a better solution, just don't know if it is possible to model in fluent. nIn my case, I'm trying to simulate a non-return valve. nIs it possible to model it by using a porous media that doesn't allow reverse flow?nAppreciate any helpnnnn

[YasserSelima]

There are many models and tools available on Fluent to help you achieve your goal. nExecute Commands as I mentioned earlier will enable you to change the boundary type or do whatever you want, in your case, You need to change the boundary from wall to interface and the opposite. I did not use execute commands before but it works with time, not pressure (Not sure if it can work with flow variables or not). Check the user guide ..nAnother tool is Events, under dynamic mesh, you can use events where you can insert/remove boundary and change boundary type. However, it works only at certain time ... nPorous material is actually a smart idea ... but you will require UDF to set the properties of the porous media based on the pressure. You can create a report definition to calculate the average pressure at the wall valve and you can read this from your UDF ... and based on this you can change the properties of your porous material. nAnother tool is to actually use a dynamic mesh SDOF and make your valve rotate as a real spring loaded non-return valve ... and make a limitation for the movement, so it does move towards one side only. You can read the report definition pressure value and change the properties (Make it lighter or heavier) based on the pressure.nnCheck these 4 and read the manual and take a decision. I would start by checking the porous media optio

[Rob]

Porous media isn't a bad idea. There are also source terms and FIX cell zone functions. All will need a UDF or maybe an expression to set the flow; you want the correct syntax for nIF vmag<=0 vmag=0 Be aware that may make for an unstable model so convergence may be a little tricky. n