## Description

Chrono::FSI simulation parameters.

## Public Attributes | |

char | out_name [256] |

int3 | gridSize |

dx, dy, dz distances between particle centers. | |

Real3 | worldOrigin |

Real3 | cellSize |

uint | numBodies |

Real3 | boxDims |

Dimensions of the domain. How big is the box that the domain is in. | |

Real | HSML |

Interaction Radius (or h). | |

Real | MULT_INITSPACE |

Multiplier to hsml to determine the initial separation of the fluid particles and the fixed separation for the boundary particles. More... | |

Real | MULT_INITSPACE_Cables |

Real | MULT_INITSPACE_Shells |

Real | epsMinMarkersDis |

epsilon mult for minimum distance between markers (d_min = eps * HSML) | |

int | NUM_BOUNDARY_LAYERS |

Number of particles layers that will be used in the boundary. Default value = 3. | |

Real | toleranceZone |

Helps determine the particles that are in the domain but are outside the boundaries, so they are not considered fluid particles and are dropped at the beginning of the simulation. More... | |

int | NUM_BCE_LAYERS |

Number of fixed particle layers to rigid/flexible bodies which act as the boundaries. More... | |

Real | solidSurfaceAdjust |

Real | BASEPRES |

Relative value of pressure applied to the whole domain. | |

Real | LARGE_PRES |

Artificial pressure for boundary particles. More... | |

Real3 | deltaPress |

Change in Pressure. More... | |

Real3 | V_in |

Inlet Velocity. This is needed for inlet BC. | |

Real | x_in |

Real3 | gravity |

Gravity. Applied to fluid, rigid and flexible. | |

Real3 | bodyForce3 |

Constant force applied to the fluid. More... | |

Real | rho0 |

Density. | |

Real | rho_solid |

Solid Density. | |

Real | markerMass |

marker mass | |

Real | mu0 |

Viscosity. | |

Real | kappa |

surface tension parameter | |

Real | v_Max |

Max velocity of fluid used in equation of state. | |

Real | EPS_XSPH |

Method to modify particle velocity. | |

Real | beta_shifting |

beta coefficient in the shifting vector formula. | |

Real | dT |

Time step. | |

Real | dT_Flex |

Real | Co_number |

Real | dT_Max |

int | out_fps |

Real | tFinal |

Total simulation time. | |

Real | timePause |

Time that we let pass before applying body forces. More... | |

Real | timePauseRigidFlex |

Time before letting rigid/flex move. More... | |

Real | kdT |

Implicit integration parameter. Not very important. | |

Real | gammaBB |

Equation of state parameter. | |

Real3 | cMin |

Lower leftmost part of the space shown in a simulation frame. More... | |

Real3 | cMax |

Upper right most part of the space shown in a simulation frame. More... | |

bool | ApplyInFlowOutFlow |

Real3 | inflow |

Real3 | outflow |

Real3 | cMinInit |

[ TODO : this need to be added to check point ] | |

Real3 | cMaxInit |

[ TODO : this need to be added to check point ] | |

Real3 | straightChannelBoundaryMin |

Origin of the coordinate system (Point (0,0,0)). More... | |

Real3 | straightChannelBoundaryMax |

Upper right most part of the system, this is Point(2 * mm, 1 * mm, 3 * mm) where mm is a constant defined at the beginning of main.cpp. More... | |

Real | binSize0 |

Suggests the length of the bin each particle occupies. More... | |

Real3 | rigidRadius |

Radius of rigid bodies. | |

int | densityReinit |

Reinitialize density after densityReinit steps. More... | |

int | contactBoundary |

0: straight channel, 1: serpentine | |

BceVersion | bceType |

Type of boundary conditions, ADAMI or mORIGINAL. | |

bool | Conservative_Form |

Whether conservative or consistent discretization should be used. | |

bool | USE_NonIncrementalProjection |

Used in the I2SPH implementation. | |

bool | DensityBaseProjetion |

bool | USE_LinearSolver |

Use direct linear solver; if false, use iterative method. | |

bool | Pressure_Constraint |

Whether the singularity of the pressure equation should be fixed. | |

ChFsiLinearSolver::SolverType | LinearSolver |

Type of the linear solver. | |

Real | LinearSolver_Abs_Tol |

Poisson Pressure Equation residual. | |

Real | LinearSolver_Rel_Tol |

Poisson Pressure Equation Absolute residual. | |

int | LinearSolver_Max_Iter |

Linear Solver maximum number of iteration. | |

bool | Verbose_monitoring |

Poisson Pressure Equation Absolute residual. | |

Real | Max_Pressure |

Max Pressure in the pressure solver. | |

PPE_SolutionType | PPE_Solution_type |

MATRIX_FREE, FORM_SPARSE_MATRIX see Rakhsha et al. More... | |

Real | PPE_relaxation |

bool | ClampPressure |

Clamp pressure to 0 if negative, based on IISPH paper by Ihmsen et al. (2013) | |

Real | IncompressibilityFactor |

Real | Cs |

bool | Adaptive_time_stepping |

Only with IISPH for now. | |

bool | Apply_BC_U |

This option lets you apply a velocity BC on the BCE markers. | |

Real | L_Characteristic |

Some length characteristic for Re number computation. | |

## Member Data Documentation

Real chrono::fsi::SimParams::binSize0 |

Suggests the length of the bin each particle occupies.

Normally this would be 2*hsml since hsml is the radius of the particle, but when we have periodic boundary condition varies a little from 2*hsml. This may change slightly due to the location of the periodic BC.

Real3 chrono::fsi::SimParams::bodyForce3 |

Constant force applied to the fluid.

Flexible and rigid bodies are not affected by this force directly, but instead they are affected indirectly through the fluid.

Real3 chrono::fsi::SimParams::cMax |

Upper right most part of the space shown in a simulation frame.

This point is usually outside the tolerance zone.

Real3 chrono::fsi::SimParams::cMin |

Lower leftmost part of the space shown in a simulation frame.

This point is usually outside the tolerance zone.

Real3 chrono::fsi::SimParams::deltaPress |

Change in Pressure.

This is needed for periodic BC. The change in pressure of a particle when it moves from end boundary to beginning.

int chrono::fsi::SimParams::densityReinit |

Reinitialize density after densityReinit steps.

Note that doing this more frequently helps in getting more accurate incompressible fluid, but more stable solution is obtained for larger densityReinit

Real chrono::fsi::SimParams::LARGE_PRES |

Artificial pressure for boundary particles.

Make sure fluid particles do not go through the boundaries. Note that if time step is not small enough particles near the boundaries might build up huge pressures and will make the simulation unstable.

Real chrono::fsi::SimParams::MULT_INITSPACE |

Multiplier to hsml to determine the initial separation of the fluid particles and the fixed separation for the boundary particles.

This means that the separation will always be a multiple of hsml. Default value = 1.0.

int chrono::fsi::SimParams::NUM_BCE_LAYERS |

Number of fixed particle layers to rigid/flexible bodies which act as the boundaries.

Default value = 2.

PPE_SolutionType chrono::fsi::SimParams::PPE_Solution_type |

MATRIX_FREE, FORM_SPARSE_MATRIX see Rakhsha et al.

2018 paper for details omega relaxation in the pressure equation, something less than 0.5 is necessary for Jacobi solver

Real3 chrono::fsi::SimParams::straightChannelBoundaryMax |

Upper right most part of the system, this is Point(2 * mm, 1 * mm, 3 * mm) where mm is a constant defined at the beginning of main.cpp.

This is also the rightmost particle of the 3rd layer of the top boundary particles. Everything above this point is not considered part of the system.

Real3 chrono::fsi::SimParams::straightChannelBoundaryMin |

Origin of the coordinate system (Point (0,0,0)).

In this case (straigh channel) this point is where the leftmost particle of the 3rd layer of boundary particles is located. Everything below this point is outside the tolerance zone, this means that everything below is not considered part of the system.

Real chrono::fsi::SimParams::timePause |

Time that we let pass before applying body forces.

This is done to allow the particles to stabilize first. Run the fluid only during this time, with dTm = 0.1 * dT

Real chrono::fsi::SimParams::timePauseRigidFlex |

Time before letting rigid/flex move.

Keep the rigid and flex stationary during this time (timePause + timePauseRigidFlex) until the fluid is fully developed

Real chrono::fsi::SimParams::toleranceZone |

Helps determine the particles that are in the domain but are outside the boundaries, so they are not considered fluid particles and are dropped at the beginning of the simulation.