Hello,

I have been modeling steady state vehicle aerodynamics for a few years now and I am faced with a simple problem yet I can't seem to get a solution, can anybody help me?

I have a land rover and a livestock trailer. In most of my simulations of turbulent flow, air flows through a duct surrounding the vehicles and that is simple enough. However, I want to look at a flow speed of zero.

There are CAD models of animals which I have inside the livestock trailer and they produce heat. I just want to model the temperature gradients inside the trailer. I have followed the help in Fluent and changed the boundary conditions of the duct I used for airflow calculations. So now, all the external boundaries are pressure outlets at asmospheric pressure and the vehicles and animals are walls. However, the solution always diverges.

What am I doing wrong!?! Can anybody give me a simple overview of the steps required to model this type of flow? Thank you for your time. Best regards,

Carlos.

Use body force weighted for pressure, gravity enabled, ideal gas and ensure boundaries are far enough away from heat source

Are you specifying isothermal wall as BC for the livestocks or u treat them as conjugate heat transfering sources with volumetric heat generation. I agree with red melon you need to specify the gravity as -9.81m/s2, and enable ideal gas assumption. Its not a must to have the boundary quite far away as u r specifying pressure BC.