Negative absolute pressure

Hello I have the problem with the negative absolute pressure of the model material and can't understand where is my mistake. My model is like the 'cavity rotating' from examples of Acusolve help, but with inflow and outflow. I have the Mass Flux and Pressure in the inlet. When I use the constant model of the material it work, but I need to use the ideal model of air.

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ydigit

I am not sure why would you define a Reference Frame for a square surface (that is probably not suppose to rotate).

Could you describe what problem are you trying to solve and which 'cavity rotatiting' example are you referring to from AcuSolve Help (There are over 50 validation examples!) ?

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ydigit

I also noticed, that there are BCwarnings, when trying to run this case. Two surfaces were not assigned Boundary Conditions. All surfaces that come in contact with fluid need to have BCs, to avoid warnings (and errors).

Typically to run a case with ideal gas, it is recommended to use restart from an incompressible (constant) properties case.

Altair Forum User

I am not sure why would you define a Reference Frame for a square surface (that is probably not suppose to rotate).

Could you describe what problem are you trying to solve and which 'cavity rotatiting' example are you referring to from AcuSolve Help (There are over 50 validation examples!) ?

Hello, I said about example named: 'Flow Inside a Rotating Cavity' (First Image). The file that I attached, I cut a small portion of the sector (green area), in order to simplify the calculation (2nd Image). The circle has a thickness of 3 microns and it is necessary that one of its surfaces rotated at speed 1256.64 rad/sec.

<?xml version="1.0" encoding="UTF-8"?>

acupro

You'll often see issues at startup using Ideal Gas if the initial conditions are not physically consistent. You may try running with constant properties, using BCs that are correct for the ideal gas case, then restart (or use the solution as initial conditions) to switch to ideal gas.

Altair Forum User

You'll often see issues at startup using Ideal Gas if the initial conditions are not physically consistent. You may try running with constant properties, using BCs that are correct for the ideal gas case, then restart (or use the solution as initial conditions) to switch to ideal gas.

Could you correct my example and upload it here?