Definitions

• Area—Area (m2) of a Boundary or Interface.

• Average Static Pressure—Average static pressure in a selected Volume of the fluid.

• Averaged Total Pressure—Area averaged value of the total pressure at a Boundary or Interface, based on

where the summations are over all the faces associated with the boundary. The unit of averaged total pressure (also known as mass averaged total pressure) is Pascal (N/m2).

• Axial Velocity Component—Fluid velocity (N/m) in the direction of the Rotational Axis Vector [x, y, z].

• Blanked—An option not to solve for a primary variable in a selected Volume.

• Effective Viscosity—Effective dynamic viscosity (Poise or Pa-s), are computed by the Turbulence module, and used instead of the laminar viscosity in the Flow module formulation. Effective viscosity does not include the effects of vapor or aeration. Effective viscosity is assumed to be Newtonian, for example, the shearing effects are not included.

• Gravity Force—Incorporates the effects of a gravitational field or acceleration in the Flow module by activating the gravity force option to Yes and specifying a gravity vector g. The gravity vector is expressed in terms of X, Y, Z components relative to the coordinate system. The magnitude of each component is in m/s2.

• Mach Number—Velocity divided by the speed of sound. The mach number is computed for compressible fluids, for example an Ideal Gas.

• Mass Flow Rate—Mass per second crossing a Boundary/ Interface. The unit of mass flow rate is (kg/sec).

• Max. Velocity Adjustment—Limits how large the values for the velocity correction terms for the velocity box can become in order to control solution convergence during the iteration process.

• Max. Velocity Magnitude—Limits how large the values in the velocity box can become in order to control solution convergence.

• Momentum—Momentum is mass time velocity (p=mv).

• Normal—Normal vector (X, Y, Z) at a Boundary/ Interface.

• Normal Velocity Component—Fluid velocity (m/s) normal to a Boundary.

• Power—Power about the axis of rotation for a rotating boundary. The sign of the power is power of the fluid on the Boundary, such that a positive power corresponds to work per seconds done by the fluid on the Boundary.

• Pressure—Static pressure in the fluid. The unit of static pressure is Pascal (N/m2). Specify pressure as a Gauge Pressure such as with the static pressure specified relative to a fixed reference or in absolute terms.

• Pressure Force—Force due to the normal pressure on a Boundary/ Interface. The unit of pressure force is Newton (N).

• Reference Pressure Location—For a closed system, a system that is not linked to a specified pressure, the pressure solution inside is not unique. To anchor the pressure solution, you can use the parameter reference pressure location to set the absolute pressure at a selected grid cell to zero. It is activated under the Flow module in the Properties panel. Since the reference pressure at the reference pressure location is set to zero, this option is only valid for Incompressible Flow, where the properties do not depend on pressure. Set the default value of pressure to -1. The pressure inside the domain is not fixed at any specific point, but instead depends on the Boundary Conditions.

• Revolution Averaged Mass Flux—Running average of the mass flow rate crossing a Boundary/ Interface over the last revolution. The unit of revolution averaged mass flux is (kg/sec).

• Revolution Averaged Power—Running average of the power applied to a rotating Boundary/ Interface over the last revolution. The unit of revolution averaged power is watt.

• Revolution Averaged Volumetric Flux—Running average of the volumetric flow rate crossing a Boundary/ Interface over the last revolution. The unit of revolution averaged volumetric flux is gallons/ minute (GPM).

• Rotational Axis Vector—Specifies the axis of rotation. The direction is specified in terms of a Vector [X, Y, Z] relative to the stationary (laboratory) ‘X, Y, Z’ coordinate system of the model.

• Rotational Center—Specifies the location of the rotational axis vector for a rotating entity. The rotational center is specified in terms of the [X, Y, Z] coordinate laying on the center line of the rotational axis vector. Rotational center and related rotational parameters can apply to a rotating reference frame, initial condition, boundary condition, or remeshing (moving) volume.

• Rotational Direction—Specifies the direction of rotation. The direction of rotation is specified as clockwise or counterclockwise relative to a rotational axis vector. This uses the convention that a positive clockwise rotation is based on the vantage point with the rotational axis vector pointing at the viewer.

• Rotational Speed—Specifies the speed of rotation. The units are RPM, radians per second, and degrees per second. The rotational center, rotational direction and rotational speed are used together with the rotational axis vector to determine the motion.

• Speed of Sound—Refers to the speed of sound in a compressible fluid. Speed of Sound is computed for compressible fluids, for example an ideal gas or when the Cavitation module is activated.

• Torque—Refers to the X, Y, Z components of the torque about a user-provided reference center for a rotating Boundary. The signs of the torque components are the torque of the fluid on the Boundary, using a right-hand rule relative to the respective X, Y, Z axis.

• Torque in Axis Direction—Torque about the axis of rotation for a rotating Boundary. The sign of the torque in axis direction is the torque of the fluid on the Boundary, using a right-hand rule relative to the Rotational Axis Vector. For example, a clockwise-rotating boundary produces a positive torque.

• Total Pressure—Refers to the static pressure in the fluid and the dynamic pressure. The unit of total pressure is Pascal (N/m2)

where,

ρ | density |

V | fluid velocity |

• Velocity—Velocity of the fluid in meters per second (m/s). The components of velocity are computed and output with reference to the stationary (laboratory) X, Y, Z coordinate system of the model using the components u,v,w.

• Velocity Magnitude—Magnitude of the velocity in meters per second (m/s) is expressed as follows:

• Viscosity—Dynamic viscosity (Poise or Pa-s) as used in the Flow module formulation.

• Viscous Force—Force due to the fluid shear on a boundary or interface. The unit of viscous force is Newton (N).

• Volumetric Flow Rate—Volume per second crossing a Boundary/ Interface. The unit of mass flow rate is kg/sec.

• Vorticity (X, Y, Z)—Magnitude of the local angular rate of rotation of the fluid (1/s). Mathematically, vorticity is the curl of the local velocity.

The velocity used to compute the vorticity is with reference to the stationary (laboratory) X, Y, Z coordinate system of the model.

• Vorticity Magnitude—A derived variable in the Flow module corresponding to the magnitude of the vorticity (1/s).