Description

Structure with FSI simulation parameters.

#include <ChParams.h>

Public Attributes
SPHMethod	sph_method
	SPH mehtod (WCSPH or I2SPH)

int	output_length
	Output length (0:short, 1:middle, 2:long) information of SPH particles into data files.

int3	gridSize
	dx, dy, dz distances between particle centers.

Real3	worldOrigin
	Origin point.

Real3	cellSize
	Size of the neighbor particle searching cell.

uint	numBodies
	Number of FSI bodies.

Real3	boxDims
	Dimensions of the domain. How big is the box that the domain is in.

Real	HSML
	Interaction Radius (or h)

Real	INVHSML
	1.0 / h

Real	INITSPACE
	Initial separation of the fluid particles.

Real	INV_INIT
	1.0 / INITSPACE

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

int	num_neighbors
	Number of neighbor particles.

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

int	NUM_BCE_LAYERS
	Number of BCE marker layers attached to boundary and solid surfaces. 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.

Real	BASEPRES
	Relative value of pressure applied to the whole domain.

Real3	deltaPress
	Change in Pressure. More...

Real3	V_in
	Inlet velocity. This is needed for inlet BC.

Real	x_in
	Inlet position. This is needed for inlet BC.

Real3	gravity
	Gravity. Applied to fluid, rigid and flexible.

Real3	bodyForce3
	Constant force applied to the fluid. More...

Real	rho0
	Density.

Real	invrho0
	Density's inverse.

Real	rho_solid
	Solid Density.

Real	volume0
	Initial volume of particle.

Real	markerMass
	marker mass

Real	mu0
	Viscosity.

Real	kappa
	surface tension parameter

Real	v_Max
	Max velocity of fluid used in equation of state. Run simulation once to be able to determine it.

Real	EPS_XSPH
	Method to modify particle velocity.

Real	beta_shifting
	this is the beta coefficient in the shifting vector formula. See

Real	Vis_Dam
	Viscous damping force.

Real	dT
	Time step. More...

Real	INV_dT
	1.0 / dT

Real	dT_Flex
	Setpsize for the flexible bodies dynamics.

Real	Co_number
	Constant in CFL condition.

Real	dT_Max
	Maximum setpsize.

Real	kdT
	Implicit integration parameter. Not very important.

Real	gammaBB
	Equation of state parameter.

bool	use_default_limits
	true if cMin and cMax are not user-provided (default: true)

bool	use_init_pressure
	true if pressure set based on height (default: false)

Real3	cMinInit
	Minimum point of the fluid domain.

Real3	cMaxInit
	Maximum point of the fluid domain.

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.This is also the rightmost particle of the 3rd layer of the top boundaryparticles.Everything above this point is not considered part of thesystem.

Real	binSize0
	Suggests the length of the bin each particle occupies. More...

Real3	rigidRadius
	Radius of rigid bodies.

double	pressure_height
	height for pressure initialization

int	densityReinit
	Reinitialize density after densityReinit steps. More...

bool	Conservative_Form
	Whether conservative or consistent discretization should be used.

int	gradient_type
	Type of the gradient operator.

int	laplacian_type
	Type of the laplacian operator.

bool	USE_Consistent_G
	Use consistent discretization for gradient operator.

bool	USE_Consistent_L
	Use consistent discretization for laplacian operator.

bool	DensityBaseProjection
	Set true to use density based projetion scheme in ISPH solver.

bool	Pressure_Constraint
	Whether the singularity of the pressure equation should be fixed.

SolverType	LinearSolver
	Type of the linear solver.

Real	Alpha
	Poisson Pressure Equation source term constant. Used to control the noise in the FS forces.

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.

Real	PPE_relaxation
	PPE_relaxation.

bool	ClampPressure
	Clamp pressure to 0 if negative, based on the ISPH paper by Ihmsen et al. (2013)

Real	IncompressibilityFactor
	Incompressibility factor, default = 1.

Real	Cs
	Speed of sound.

bool	Adaptive_time_stepping
	Works only with ISPH for now, use Co_number can be used as the criteria for adaptivity. More...

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.

bool	non_newtonian
	Set true to model non-newtonian fluid.

Rheology	rheology_model
	Model of the rheology.

Real	ave_diam
	average particle diameter

Real	cohesion
	c in the stress model sigma=(mu*p+c)/\|D\|

FrictionLaw	mu_of_I
	Constant I in granular material dyanmcis.

Real	mu_max
	maximum viscosity

Real	mu_fric_s
	friction mu_s

Real	mu_fric_2
	mu_2 constant in mu=mu(I)

Real	mu_I0
	Reference Inertia number.

Real	mu_I_b
	b constant in mu=mu(I)=mu_s+b*I

Real	HB_sr0
	Herschel–Bulkley consistency index.

Real	HB_k
	Herschel–Bulkley consistency index.

Real	HB_n
	Herschel–Bulkley power.

Real	HB_tau0
	Herschel–Bulkley yeild stress.

bool	elastic_SPH
	Handles the WCSPH solver for fluid (false) or granular (true)

Real	E_young
	Young's modulus.

Real	G_shear
	Shear modulus.

Real	INV_G_shear
	1.0 / G_shear

Real	K_bulk
	Bulk modulus.

Real	Nu_poisson
	Poisson’s ratio.

Real	Ar_stress
	Artifical stress.

Real	Ar_vis_alpha
	Artifical viscosity coefficient.

Real	Ar_vis_beta
	Artifical viscosity coefficient.

Real	Fri_angle
	Frictional angle of granular material.

Real	Dil_angle
	Dilate angle of granular material.

Real	Coh_coeff
	Cohesion coefficient.

Real	Q_FA
	Material constants calculate from frictional angle.

Real	Q_DA
	Material constants calculate from dilate angle.

Real	K_FA
	Material constants calculate from frictional angle and cohesion coefficient.

Real	C_Wi
	Threshold of the integration of the kernel function.

Real	boxDimX
	Dimension of the space domain - X.

Real	boxDimY
	Dimension of the space domain - Y.

Real	boxDimZ
	Dimension of the space domain - Z.

Real3	cMin
	Lower limit point.

Real3	cMax
	Upper limit point.

Real3	bodyActiveDomain
	Size of the active domain that influenced by an FSI body.

Real	settlingTime
	Time for the granular to settle down.

int	num_proximity_search_steps
	Number of steps between updates to neighbor lists.

Member Data Documentation

◆ Adaptive_time_stepping

bool chrono::fsi::SimParams::Adaptive_time_stepping

Works only with ISPH for now, use Co_number can be used as the criteria for adaptivity.

dT_Max is set either from the Co_number, or the time step the is required for outputting data

◆ binSize0

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.

◆ bodyForce3

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.

◆ deltaPress

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.

◆ densityReinit

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

◆ dT

Real chrono::fsi::SimParams::dT

Time step.

Depending on the model this will vary and the only way to determine what time step to use is to run simulations multiple time and find which one is the largest dT that produces a stable simulation.

◆ MULT_INITSPACE

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.

◆ straightChannelBoundaryMin

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

The documentation for this struct was generated from the following file:

/builds/uwsbel/chrono/src/chrono_fsi/physics/ChParams.h