Step 4: Materials

Materials

  The default Fluid Material is air, which is the working fluid in this problem. The default settings need to be modified to account for compressibility and variations of the thermophysical properties with temperature.

1.   Set the properties for air, the default fluid material.

Materials air Create/Edit...

(a)   Select ideal-gas from the Density drop-down list.

  The Energy Equation will be enabled.

(b)   Select sutherland from the Viscosity drop-down list to open the Sutherland Law dialog box.

  Scroll down the Viscosity drop-down list to find sutherland.

i.   Retain the default selection of Three Coefficient Method in the Methods list.

ii.   Click OK to close the Sutherland Law dialog box.

  The Sutherland law for viscosity is well suited for high-speed compressible flows.

(c)   Click Change/Create to save these settings.

(d)   Close the Create/Edit Materials dialog box.

  While Density and Viscosity have been made temperature dependent, Cp and Thermal Conductivity have been left constant. For high-speed compressible flows, thermal dependency of the physical properties is generally recommended. For simplicity, Thermal Conductivity and Cp are assumed to be constant in this tutorial.