incflo Class Reference

#include <incflo.H>

Inheritance diagram for incflo:

Collaboration diagram for incflo:

Public Member Functions
	incflo ()
	~incflo () override
void	InitData ()
void	Evolve ()
void	Evolve_MultiBlock (int multiblock_step, int max_block_step)
void	ErrorEst (int lev, amrex::TagBoxArray &tags, amrex::Real time, int ngrow) override
void	MakeNewLevelFromScratch (int lev, amrex::Real time, const amrex::BoxArray &new_grids, const amrex::DistributionMapping &new_dmap) override
void	MakeNewLevelFromCoarse (int lev, amrex::Real time, const amrex::BoxArray &ba, const amrex::DistributionMapping &dm) override
void	RemakeLevel (int lev, amrex::Real time, const amrex::BoxArray &ba, const amrex::DistributionMapping &dm) override
void	ClearLevel (int lev) override
void	init_mesh ()
void	init_amr_wind_modules ()
void	prepare_for_time_integration ()
bool	regrid_and_update ()
void	pre_advance_stage1 ()
void	pre_advance_stage2 ()
void	prepare_time_step ()
void	do_advance (const int fixed_point_iteration)
void	advance (const int fixed_point_iteration)
void	prescribe_advance ()
void	post_advance_work ()
amr_wind::CFDSim &	sim ()
const amr_wind::SimTime &	time () const
amr_wind::FieldRepo &	repo ()
const amr_wind::FieldRepo &	repo () const
amr_wind::pde::PDEBase &	icns ()
const amr_wind::pde::PDEBase &	icns () const
amr_wind::pde::PDEMgr::TypeVector &	scalar_eqns ()
const amr_wind::pde::PDEMgr::TypeVector &	scalar_eqns () const
amr_wind::Field &	velocity () const
amr_wind::Field &	density () const
amr_wind::Field &	temperature () const
amr_wind::Field &	pressure () const
amr_wind::Field &	grad_p () const
void	ComputeDt (bool explicit_diffusion)
void	ComputePrescribeDt ()
void	ApplyPredictor (const bool incremental_projection=false, const int fixed_point_iteration=0)
void	ApplyCorrector ()
void	ApplyPrescribeStep ()
void	ApplyProjection (amrex::Vector< amrex::MultiFab const * > density, amrex::Real time, amrex::Real scaling_factor, bool incremental)
void	init_physics_and_pde ()
	Initialize Physics instances as well as PDEs (include turbulence models)
void	ReadCheckpointFile ()
void	SetMultiBlockPointer (MultiBlockContainer *mbc)
void	set_read_erf (ReadERFFunction fcn)

Private Member Functions
amrex::FabFactory< amrex::FArrayBox > const &	Factory (int lev) const noexcept
bool	need_divtau () const
void	CheckAndSetUpDryRun ()
void	ReadParameters ()
void	InitialProjection ()
void	InitialIterations ()
void	PrintMaxValues (const std::string &header)
void	PrintMaxVelLocations (const std::string &header)
void	PrintMaxVel (int lev) const
void	PrintMaxGp (int lev) const
void	CheckForNans (int lev) const

Private Attributes
amr_wind::CFDSim	m_sim
amr_wind::SimTime &	m_time
amr_wind::FieldRepo &	m_repo
amr_wind::OversetOps	m_ovst_ops
std::unique_ptr< amr_wind::RefineCriteriaManager >	m_mesh_refiner
int	m_verbose = 0
bool	m_do_initial_proj = true
int	m_initial_iterations = 3
bool	m_use_godunov = true
bool	m_prescribe_vel = false
bool	m_dry_run = false
int	m_fixed_point_iterations {1}
amrex::Long	m_cell_count {-1}
	number of cells on all levels including covered cells
DiffusionType	m_diff_type = DiffusionType::Crank_Nicolson
bool	m_reconstruct_true_pressure {false}
	reconstruct true pressure

Detailed Description

AMR-Wind driver class

Constructor & Destructor Documentation

incflo()

incflo::incflo

(

)

~incflo()

incflo::~incflo ( )

overridedefault

Member Function Documentation

advance()

void incflo::advance

(

const int

fixed_point_iteration

)

Advance simulation state by one timestep

Performs the following actions at a given timestep

• Compute $\Delta t$
• Advance all computational fields to new timestate in preparation for time integration
• Call pre-advance work for all registered physics modules
• For Godunov scheme, advance to new time state
• For MOL scheme, call predictor corrector steps
• Perform any post-advance work

Much of the heavy-lifting is done by incflo::ApplyPredictor and incflo::ApplyCorrector. Please refer to the documentation of those methods for detailed information on the various equations being solved.

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ApplyCorrector()

void incflo::ApplyCorrector

(

)

Corrector step for MOL scheme

1. Solve transport equation for momentum and scalars

   $$\begin{align} \left[1 - \kappa \frac{\Delta t}{\rho} \nabla \cdot \left( \mu \nabla \right)\right] u^{*} &= u^n - \Delta t C_u + (1 - \kappa) \frac{\Delta t}{\rho} \nabla \cdot \left( \mu \nabla\right) u^{n} + \frac{\Delta t}{\rho} \left( S_u - \nabla(p + p_0)\right) \\ \end{align}$$

   where

   $$\begin{align} \kappa = \begin{cases} 0 & \text{Explicit} \\ 0.5 & \text{Crank-Nicolson} \\ 1 & \text{Implicit} \end{cases} \end{align}$$

2. Apply projection

ApplyPredictor()

void incflo::ApplyPredictor	(	const bool	incremental_projection = false,
		const int	fixed_point_iteration = 0 )

Apply predictor step

For Godunov, this completes the timestep. For MOL, this is the first part of the predictor/corrector within a timestep.

1. Solve transport equation for momentum and scalars

   $$\begin{align} \left[1 - \kappa \frac{\Delta t}{\rho^{n+1/2}} \nabla \cdot \left( \mu \nabla \right)\right] u^{*} &= u^n - \Delta t (u \cdot \nabla) u + (1 - \kappa) \frac{\Delta t}{\rho^n} \nabla \cdot \left( \mu^{n} \nabla\right) u^{n} + \frac{\Delta t}{\rho^{n+1/2}} \left( S_u - \nabla(p + p_0)\right) \\ \end{align}$$

   where

   $$\begin{align} \kappa = \begin{cases} 0 & \text{Explicit} \\ 0.5 & \text{Crank-Nicolson} \\ 1 & \text{Implicit} \end{cases} \end{align}$$

2. Apply projection

ApplyPrescribeStep()

void incflo::ApplyPrescribeStep

(

)

ApplyProjection()

void incflo::ApplyProjection	(	amrex::Vector< amrex::MultiFab const * >	density,
		amrex::Real	time,
		amrex::Real	scaling_factor,
		bool	incremental )

Perform nodal projection

Computes the following decomposition:

$$\begin{align} u + \frac{\Delta t}{\rho} \nabla \phi &= u^{*} & \nabla \cdot u = 0 \end{align}$$

where $u^{*}$ is a non-div-free velocity field, stored by components in u, v, and w. The resulting div-free velocity field, u, overwrites the value of u* in u, v, and w.

$\phi$ is an auxiliary function related to the pressure $p$ by the relation:

$$p^{\mathrm{new}} = \phi$$

except in the initial projection when

$$p^{\mathrm{new}} = p^{\mathrm{old}} + \phi$$

Velocity is updated using the following relation

$$\begin{align} u^{**} &= u^{*} + \frac{\Delta t}{\rho} \nabla p^{\mathrm{old}} \\ \nabla \cdot \left( \frac{\Delta t}{\rho} \nabla \phi \right) &= \nabla \cdot u^{**} \\ u^{\mathrm{new}} &= u^{**} - \frac{\Delta t}{\rho} \nabla p^\mathrm{new} \end{align}$$

Notes:

• scaling_factor equals $\Delta t$ except when called during initial projection, when it is 1.0
• $\rho$ in the above expressions is either at state n+1 or n+1/2 depending on whether this method was called from incflo::ApplyPredictor or incflo::ApplyCorrector.
• If incremental == true, then the pressure term is not added to $u^{**}$ and the update is in delta-form.

Please consult AMReX Linear Solvers documentation for more information on the nodal projection operator.

Parameters

density	Vector of multifabs containing the density field at all levels
time	Current time
scaling_factor	Scaling factor $\Delta t$
incremental	Flag indicating if it is an incremental projection.

CheckAndSetUpDryRun()

void incflo::CheckAndSetUpDryRun ( )

private

CheckForNans()

void incflo::CheckForNans ( int lev ) const

private

ClearLevel()

void incflo::ClearLevel ( int lev )

override

ComputeDt()

void incflo::ComputeDt

(

bool

explicit_diffusion

)

Estimate the new timestep for adaptive timestepping algorithm

Parameters

explicit_diffusion

Flag indicating whether user has selected explicit treatment of diffusion term.

Compute new $\Delta t$ by using the formula derived in "A Boundary Condition Capturing Method for Multiphase Incompressible Flow" by Kang et al. (JCP).

$$\begin{align} \text{CFL} &= \frac{\Delta t}{2} \left[\left(C+V \right) + \sqrt{\left(C+V\right)^2 + 4 \left(\frac{|F_x|}{\Delta x} + \frac{|F_y|}{\Delta y} + \frac{|F_z|}{\Delta z} \right)} \right] && \\ C &= \text{max} \left(\frac{|U_x|}{\Delta x} ,\ \frac{|U_y|}{\Delta y} ,\ \frac{|U_z|}{\Delta z}\right) && \text{Convection} \\ V &= 2 \left(\frac{\mu}{\rho}\right)_\mathrm{max} \left[\frac{1}{\Delta x^2} + \frac{1}{\Delta y^2} + \frac{1}{\Delta z^2} \right] && \text{Diffusion} \end{align}$$

$F_x, F_y, F_z$ are acceleration due to forcing terms. By default, $C$ is always used for computing CFL. The term $V$ is only used when the user has chosen implicit or Crank-Nicolson scheme for diffusion, and contributions from forcing term when time.use_force_cfl is true (default is true).

ComputePrescribeDt()

void incflo::ComputePrescribeDt

(

)

density()

amr_wind::Field & incflo::density ( ) const

inline

do_advance()

void incflo::do_advance

(

const int

fixed_point_iteration

)

ErrorEst()

void incflo::ErrorEst ( int lev, amrex::TagBoxArray & tags, amrex::Real time, int ngrow )

override

Evolve()

void incflo::Evolve

(

)

Perform time-integration for user-defined time or timesteps.

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Evolve_MultiBlock()

void incflo::Evolve_MultiBlock	(	int	multiblock_step,
		int	max_block_step )

Factory()

amrex::FabFactory< amrex::FArrayBox > const & incflo::Factory ( int lev ) const

inlineprivatenoexcept

grad_p()

amr_wind::Field & incflo::grad_p ( ) const

inline

icns() [1/2]

amr_wind::pde::PDEBase & incflo::icns ( )

inline

icns() [2/2]

const amr_wind::pde::PDEBase & incflo::icns ( ) const

inline

init_amr_wind_modules()

void incflo::init_amr_wind_modules

(

)

Initialize AMR-Wind data structures after mesh has been created.

Modules initialized:

• Registered Physics models classes
• Registered PDE systems
• Registered post-processing classes

init_mesh()

void incflo::init_mesh

(

)

Initialize AMR mesh data structure.

Calls the AmrMesh/AmrCore functions to initialize the mesh. For restarted simulations, it loads the checkpoint file.

init_physics_and_pde()

void incflo::init_physics_and_pde

(

)

Initialize Physics instances as well as PDEs (include turbulence models)

InitData()

void incflo::InitData

(

)

Perform all initialization actions for AMR-Wind.

This is a wrapper method that calls the following methods to perform the actual work.

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InitialIterations()

void incflo::InitialIterations ( )

private

Perform initial pressure iterations

Performs a user-defined number of iterations to compute the pressure based on the initial conditions. This method is only invoked for new simulations and skipped for restarted simulations from a checkpoint file.

InitialProjection()

void incflo::InitialProjection ( )

private

Ensure initial velocity field is divergence-free.

Performs a projection step to ensure that the user-provided initial velocity field is divergence free. This method is only invoked for new simulations. For restarted simulations using a checkpoint file, this is not necessary.

MakeNewLevelFromCoarse()

void incflo::MakeNewLevelFromCoarse ( int lev, amrex::Real time, const amrex::BoxArray & ba, const amrex::DistributionMapping & dm )

override

MakeNewLevelFromScratch()

void incflo::MakeNewLevelFromScratch ( int lev, amrex::Real time, const amrex::BoxArray & new_grids, const amrex::DistributionMapping & new_dmap )

override

need_divtau()

bool incflo::need_divtau ( ) const

inlineprivate

post_advance_work()

void incflo::post_advance_work

(

)

Perform actions after a timestep

Performs any necessary I/O before advancing to next timestep

pre_advance_stage1()

void incflo::pre_advance_stage1

(

)

pre_advance_stage2()

void incflo::pre_advance_stage2

(

)

prepare_for_time_integration()

void incflo::prepare_for_time_integration

(

)

Initialize flow-field before performing time-integration.

This method calls the incflo::InitialProjection step to ensure that the velocity field is divergence free. Then it performs a user-defined number of initial iterations to compute $p^{n - 1/2}$ necessary for advancing into the first timestep. These actions are only performed when starting a new simulation, but not for a restarted simulation.

prepare_time_step()

void incflo::prepare_time_step

(

)

prescribe_advance()

void incflo::prescribe_advance

(

)

pressure()

amr_wind::Field & incflo::pressure ( ) const

inline

PrintMaxGp()

void incflo::PrintMaxGp ( int lev ) const

private

PrintMaxValues()

void incflo::PrintMaxValues ( const std::string & header )

private

PrintMaxVel()

void incflo::PrintMaxVel ( int lev ) const

private

PrintMaxVelLocations()

void incflo::PrintMaxVelLocations ( const std::string & header )

private

ReadCheckpointFile()

void incflo::ReadCheckpointFile

(

)

ReadParameters()

void incflo::ReadParameters ( )

private

Parse the input file and populate parameters

regrid_and_update()

bool incflo::regrid_and_update

(

)

Perform regrid actions at a given timestep.

Returns

Flag indicating if regrid was performed

RemakeLevel()

void incflo::RemakeLevel ( int lev, amrex::Real time, const amrex::BoxArray & ba, const amrex::DistributionMapping & dm )

override

repo() [1/2]

amr_wind::FieldRepo & incflo::repo ( )

inline

repo() [2/2]

const amr_wind::FieldRepo & incflo::repo ( ) const

inline

scalar_eqns() [1/2]

amr_wind::pde::PDEMgr::TypeVector & incflo::scalar_eqns ( )

inline

scalar_eqns() [2/2]

const amr_wind::pde::PDEMgr::TypeVector & incflo::scalar_eqns ( ) const

inline

set_read_erf()

void incflo::set_read_erf ( ReadERFFunction fcn )

inline

SetMultiBlockPointer()

void incflo::SetMultiBlockPointer ( MultiBlockContainer * mbc )

inline

sim()

amr_wind::CFDSim & incflo::sim ( )

inline

temperature()

amr_wind::Field & incflo::temperature ( ) const

inline

time()

const amr_wind::SimTime & incflo::time ( ) const

inline

velocity()

amr_wind::Field & incflo::velocity ( ) const

inline

Member Data Documentation

m_cell_count

amrex::Long incflo::m_cell_count {-1}

private

number of cells on all levels including covered cells

m_diff_type

DiffusionType incflo::m_diff_type = DiffusionType::Crank_Nicolson

private

m_do_initial_proj

bool incflo::m_do_initial_proj = true

private

m_dry_run

bool incflo::m_dry_run = false

private

m_fixed_point_iterations

int incflo::m_fixed_point_iterations {1}

private

m_initial_iterations

int incflo::m_initial_iterations = 3

private

m_mesh_refiner

std::unique_ptr<amr_wind::RefineCriteriaManager> incflo::m_mesh_refiner

private

m_ovst_ops

amr_wind::OversetOps incflo::m_ovst_ops

private

m_prescribe_vel

bool incflo::m_prescribe_vel = false

private

m_reconstruct_true_pressure

bool incflo::m_reconstruct_true_pressure {false}

private

reconstruct true pressure

m_repo

amr_wind::FieldRepo& incflo::m_repo

private

m_sim

amr_wind::CFDSim incflo::m_sim

private

m_time

amr_wind::SimTime& incflo::m_time

private

m_use_godunov

bool incflo::m_use_godunov = true

private

m_verbose

int incflo::m_verbose = 0

private

---

The documentation for this class was generated from the following files:

• /home/runner/work/amr-wind/amr-wind/amr-wind/incflo.H
• /home/runner/work/amr-wind/amr-wind/amr-wind/incflo.cpp
• /home/runner/work/amr-wind/amr-wind/amr-wind/incflo_advance.cpp
• /home/runner/work/amr-wind/amr-wind/amr-wind/incflo_compute_dt.cpp
• /home/runner/work/amr-wind/amr-wind/amr-wind/incflo_regrid.cpp
• /home/runner/work/amr-wind/amr-wind/amr-wind/projection/incflo_apply_nodal_projection.cpp
• /home/runner/work/amr-wind/amr-wind/amr-wind/setup/init.cpp
• /home/runner/work/amr-wind/amr-wind/amr-wind/utilities/diagnostics.cpp
• /home/runner/work/amr-wind/amr-wind/amr-wind/utilities/io.cpp