24.3.2 Modeling Open Channel Wave Boundary Conditions

When modeling open channel wave boundary conditions, many of the variables that are used in open channel flow, also exist for open channel wave boundary conditions. You may have to refer to Section  24.3.1 for information about some of the settings.

To use the open channel wave boundary condition, perform the following:

1.   Enable Gravity and set the gravitational acceleration fields.

General

2.   Enable the Volume of Fluid model in the Multiphase Model dialog box.

Models Multiphase Edit...

3.   Under Scheme, select either Implicit or Explicit.

4.   Under Volume Fraction Parameters, select Open Channel Wave BC.

In order to set specific parameters for a particular boundary for open channel wave boundaries, enable the Open Channel Wave BC option in the Velocity Inlet boundary condition dialog box (Figure  24.3.2).

Figure 24.3.2: The Velocity Inlet for Open Channel Wave BC

In the Momentum tab of the Velocity Inlet dialog box, enter the following wave specific variables:

• Wave Velocity Specification Method which can be Magnitude, Normal to Boundary or Magnitude and Direction.

• Uniform Wave Velocity Magnitude which can be specified as a Constant or a New Input Parameter....

In the Multiphase tab (Figure  24.3.3), you will specify the following:

Figure 24.3.3: The Velocity Inlet for Open Channel Wave BC

• Wave BC Options of which you have a choice of Shallow Waves or Short Gravity Waves. Information about the two types of waves is available in this section in the separate Theory Guide. Note that the short gravity waves expression is derived under the assumption of infinite liquid height.

• Secondary Phase for Inlet is where the specified parameters are valid only for one secondary phase. In case of a three-phase flow, select the corresponding secondary phase from this list.

• Wave Amplitude is the amplitude of the shallow or short gravity waves.

• Wave Length is the wavelength of the shallow or short gravity waves.

• Free Surface Level is the same definition as for open channel flow, Section  24.3.1.

• Bottom Level is the same definition as for open channel flow, Section  24.3.1, and is valid only for shallow waves. The bottom level is used for calculating the liquid height.

• Wave Heading Angle is the angle between the wave front and the flow direction, in the plane of the flow direction and cross-flow direction.

• Phase Difference is the phase angle by which one periodic disturbance or wave front lags behind or precedes another in time or space.