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-   -   Compressible flow - 2D NACA0012 Aerofoil Sim. (https://www.cfd-online.com/Forums/siemens/55480-compressible-flow-2d-naca0012-aerofoil-sim.html)

 MSc Student July 6, 2006 06:11

Compressible flow - 2D NACA0012 Aerofoil Sim.

Hi Im simulating supersonic transonic and subsonic compressible flow over a 2D NACA0012 aerofoil and Im trying to learn how to do this using the star userguide and tutorial 6 the supersonic tutorial.

Im looking to do a viscous simulation solving the N-S equations over the domain.

Ive readied my mesh and set the boundary regions. Im at the stage of setting the fluid and material properties.Ive set the density to ideal f(T,P) to make the flow compressible. But I havent seen any documentation on what to set the viscosity. Ive also set the temperature calculation to be on. So the energy equation is solved as well as the momentum and continuity. If the temperature changes and is solved across the domain then wont viscosity be changing too? In this case I cant leave the viscosity constant and its not an invisicd simulation.. so what is the best option to choose for viscous compressible flow? Ill be using the k-epsilon turbulence model and the simulation will be steady state not transient. In using version 3.24 of star-cd

 Ankush Aggarwal July 10, 2006 06:51

Re: Compressible flow - 2D NACA0012 Aerofoil Sim.

First make sure that you choose the Conservation of Stagnation Enthalpy in the temperature calculation options(as this is a compressible case) and then for viscosity you can find some table on the internet of viscosity agaionst the temperature....then you need to make a table and choose the user table in the options(i have never done that, refer to the user guide)

 MSc Student July 10, 2006 08:55

Re: Compressible flow - 2D NACA0012 Aerofoil Sim.

Ive just looked up the conservation of stagnation enthalpy in the help section and it states that stagnation enthalpy condition is: used under adiabatic, inviscid flow conditions; assumes that the total enthalpy is constant and uniform throughout the model (see equation (1-18)). Supply the value of the (constant) stagnation temperature in the Stagnation Temp. box

This doesnt make sense to me as my flow is viscous.

The conservation of total enthalpy seems to be more applicable to my situation as it states in the help total enthalpy is applicable mainly to high-speed, compressible flows.

If I do need to choose stagnation enthalpy how do I calculate the constant stagnation temperature?

 AMIR TAVAKOLI August 26, 2006 01:32

Re: Compressible flow - 2D NACA0012 Aerofoil Sim.