Inlet

The Inlet feature adds a set of boundary conditions that describe the inlets in a fluid-flow simulation. Define the Velocity boundary condition, the default mixture boundary condition for inlet boundaries, or the Pressure, no viscous stress condition.

The formulations in this boundary type all appear, some of them slightly modified, in the Outflow type as well. This means that there is nothing in the mathematical formulations that prevents a fluid from leaving the

Note

domain through boundaries where the Inlet type is specified.

B O U N D A R Y S E L E C T I O N

From the Selection list, choose the boundaries that represent inlets.

M I X T U R E B O U N D A R Y C O N D I T I O N

Select a Mixture boundary condition for the inlet—Velocity or Pressure, no viscous stress.

•If Velocity (SI unit: m/s) is selected, enter the components in the u0 fields to specify that the velocity at the boundary is equal to a given velocity vector u = u0 .

•If Pressure, no viscous stress is selected, enter the pressure p0 (SI unit: Pa) at the boundary to set the pressure to p0 and also make the viscous stress zero at the boundary:

p = p0 , + T u + u T n = 0

Mixture Boundary Condition (Turbulent Flow)

For The Mixture Model, Turbulent Flow Interface the following sections

are available.

Note

Select the Specify turbulent length scale and intensity or Specify turbulence variables

button.

•If Specify turbulent length scale and intensity is selected, enter a value for the

Turbulent intensity IT (unitless) and Turbulence length scale LT (SI unit: m). When

270 | C H A P T E R 8 : B U B B L Y F L O W A N D M I X T U R E M O D E L B R A N C H E S