Rocky Solver SDK 2026 R1

Structure IRockyCFDProperties

Last update: 09.03.2026

#include <rocky_cfd.hpp>

IRockyCFDProperties gives access to data and utility methods commonly needed for calculating interaction magnitudes between the fluid flow and a particle. The property values returned by those methods are referred either to a particle, or the CFD cell in which that particle is currently located, or both. In the special case of a 1-way constant coupling mode, as there is no CFD mesh associated, the fluid properties returned are the constant values prescribed through the Rocky UI.

Members

Public functions

Function get_fluid_density

ROCKY_FUNCTIONS double IRockyCFDProperties::get_fluid_density() const

Returns:

The value of the fluid density within the CFD cell in which the interacting particle is located.

Return type: ROCKY_FUNCTIONS double

Function get_fluid_viscosity

ROCKY_FUNCTIONS double IRockyCFDProperties::get_fluid_viscosity() const

Returns:

The value of the fluid absolute viscosity within the CFD cell in which the interacting particle is located.

Return type: ROCKY_FUNCTIONS double

Function get_fluid_temperature

ROCKY_FUNCTIONS double IRockyCFDProperties::get_fluid_temperature() const

Returns:

The value of the fluid temperature within the CFD cell in which the interacting particle is located. This temperature will be available only if the energy equation is solved in Fluent and/or thermal modeling is enabled in Rocky.

Return type: ROCKY_FUNCTIONS double

Function get_fluid_specific_heat

ROCKY_FUNCTIONS double IRockyCFDProperties::get_fluid_specific_heat() const

Returns:

The value of the fluid specific heat within the CFD cell in which the interacting particle is located.

Return type: ROCKY_FUNCTIONS double

Function get_fluid_thermal_conductivity

ROCKY_FUNCTIONS double IRockyCFDProperties::get_fluid_thermal_conductivity() const

Returns:

The value of the fluid thermal conductivity within the CFD cell in which the interacting particle is located.

Return type: ROCKY_FUNCTIONS double

Function get_fluid_pressure_gradient

ROCKY_FUNCTIONS double3 IRockyCFDProperties::get_fluid_pressure_gradient() const

Returns:

The pressure gradient in the fluid within the CFD cell in which the interacting particle is located, expressed in Cartesian coordinates.

Return type: ROCKY_FUNCTIONS double3

Function compute_fluid_vorticity

ROCKY_FUNCTIONS double3 IRockyCFDProperties::compute_fluid_vorticity() const

Returns:

The vorticity vector associated to the fluid flow within the CFD cell in which the interacting particle is located. The vorticity is defined as the curl of the fluid velocity.

Return type: ROCKY_FUNCTIONS double3

Function get_relative_velocity

ROCKY_FUNCTIONS double3 IRockyCFDProperties::get_relative_velocity() const

Returns:

The relative velocity vector in Cartesian coordinates. In this context, the relative velocity is defined as the difference between the fluid velocity and the particle velocity.

Return type: ROCKY_FUNCTIONS double3

Function get_reynolds_number

ROCKY_FUNCTIONS double IRockyCFDProperties::get_reynolds_number() const

Returns:

The Reynolds number value, based on the relative velocity and the particle's equivalent diameter. For more details, please refer to the DEM-CFD Coupling Technical Manual regarding this topic. Drag coefficients in most of the drag laws found in the literature are expressed as functions of this Reynolds number.

Return type: ROCKY_FUNCTIONS double

Function compute_vorticity_reynolds_number

ROCKY_FUNCTIONS double IRockyCFDProperties::compute_vorticity_reynolds_number() const

Returns:

The Reynolds number value, based on the flow vorticity and the particle's equivalent diameter. For more details, please refer to the DEM-CFD Coupling Technical Manual regarding this topic. Lift coefficients are usually expressed as functions of this Reynolds number.

Return type: ROCKY_FUNCTIONS double

Function compute_relative_angular_reynolds_number

ROCKY_FUNCTIONS double IRockyCFDProperties::compute_relative_angular_reynolds_number(const double3 &particle_angular_velocity) const

Returns:

The Reynolds number value, based on the relative angular velocity and the particle's equivalent diameter. For more details, please refer to the DEM-CFD Coupling Technical Manual regarding this topic. Torque laws are commonly expressed using this Reynolds number.

Parameters:

  • const double3 & particle_angular_velocity

Return type: ROCKY_FUNCTIONS double

Function get_prandtl_number

ROCKY_FUNCTIONS double IRockyCFDProperties::get_prandtl_number() const

Returns:

The Prandtl number value, defined as the ratio of the fluid's momentum diffusivity to its thermal diffusivity. For more details, please refer to the DEM-CFD Coupling Technical Manual regarding this topic.

Return type: ROCKY_FUNCTIONS double

Function get_solid_fraction

ROCKY_FUNCTIONS double IRockyCFDProperties::get_solid_fraction() const

Returns:

The solid fraction at the CFD cell in which the interacting particle is located. This parameter is defined as the ratio between the volume of the particles within that cell to the volume of the cell itself. In Fluent Two Way cases, the value of the solid fraction may be altered by a Lagrangian-to-Eulerian mapping procedure. For more details, please refer to the DEM-CFD Coupling Technical Manual.

Return type: ROCKY_FUNCTIONS double

Function get_cell_volume

ROCKY_FUNCTIONS double IRockyCFDProperties::get_cell_volume() const

Returns:

The volume of the CFD cell in which the interacting particle is located. Before calling this method, one should enable it by calling the method IRockyFluidScalarsModel::enable_storage_cell_volume()

Return type: ROCKY_FUNCTIONS double

Function get_scalars

ROCKY_FUNCTIONS IRockyFluidScalars IRockyCFDProperties::get_scalars() const

Returns:

An IRockyFluidScalars object that gives access to the values of all CFD fluid scalars defined in the project at the CFD cell in which the interacting particle is located.

Return type: ROCKY_FUNCTIONS IRockyFluidScalars

Function get_cfd_time_step

ROCKY_FUNCTIONS double IRockyCFDProperties::get_cfd_time_step() const

Returns:

The CFD time step

Return type: ROCKY_FUNCTIONS double

Connect with Ansys