To achieve a Mach number of approximately 0.75 at the inlet, isentropic relations were used to determine the inlet total pressure and outlet static pressure for a given total temperature. For an outlet static pressure equal to one atmosphere (absolute) and a static temperature of 300 K, the inlet total pressure should be 164904 Pa (absolute). The inlet total temperature will be 344.8 K.
The boundary values are specified as gauge pressures. Therefore, using the default reference pressure of 101325 Pa (one atmosphere), the inlet total pressure should be set to 63579 Pa (gauge). The outlet static pressure will be 0 Pa (gauge), the default value.
Open the subdomain-1 node in the Regions node, then open the Boundaries node. Open the Inlet, Physics Values and Total Pressure nodes, and select the Constant node.
Set the Value property to 63579.
The total pressure setting is relative to the operating pressure value of 101325 Pa. A supersonic static pressure is also required as part of a stagnation inlet condition but is only used if the inlet velocity becomes supersonic at some instance during solution iteration. The default value of 0.0 Pa relative is sufficient as long as this does not occur.
The next value to set is the total temperature. In the same Physics Values node, open the Total Temperature node and select the Constant node.
Set the Value property to 344.8.
In the same Physics Values node, open the Turbulent Viscosity Ratio node and select the Constant node.
Set the Value property to 50. This value has been determined to give a reasonable decay of turbulence in the channel core (for the default turbulence intensity).
