Restrictor, User

Properties: adiabatic, not isentropic, directional, inlet based restrictor if $A_1 < A_2$ and outlet based restrictor if $A_2 < A_1$.

A user-defined restrictor is described by the following constants (to be specified in that order on the line beneath the *FLUID SECTION, TYPE=RESTRICTOR USER card):

• upstream cross section $A_1$.
• downstream cross section $A_2$.
• hydraulic diameter $D_h$ defined by $D_h=4 A/P$ where $A$ is the area of the smallest cross section and $P$ is the perimeter of the smallest cross section.
• loss coefficient $\zeta$.
• oil mass flow in the restrictor (only if the OIL parameter is used to define the kind of oil in the *FLUID SECTION card)
• not used (internally: oil material number)

By specifying the parameter LIQUID on the *FLUID SECTION card the loss is calculated for liquids. In the absence of this parameter, compressible losses are calculated.

Example files: restrictor, restrictor-oil.