ParticlePhysics.h File Reference

Header file for Particle related physics modules. More...

#include <petsc.h>
#include <petscdmswarm.h>
#include <stdbool.h>
#include <petscsys.h>
#include <math.h>
#include "variables.h"
#include "logging.h"
#include "walkingsearch.h"

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Functions
PetscErrorCode	UpdateParticleField (const char *fieldName, PetscReal t, Cmpnts pos, Cmpnts vel, PetscReal *psi_io)
	Updates a single particle's field based on its state and the specified field name.
PetscErrorCode	UpdateFieldForAllParticles (UserCtx *user, const char *fieldName)
	Loops over all local particles and updates a specified field.
PetscErrorCode	UpdateAllParticleFields (UserCtx *user)
	Orchestrates the update of all physical properties for particles.

Detailed Description

Header file for Particle related physics modules.

This file contains declarations of functions responsible for solving for fields in the particle swarms within a simulation using PETSc's DMSwarm.

Definition in file ParticlePhysics.h.

Function Documentation

UpdateParticleField()

PetscErrorCode UpdateParticleField	(	const char *	fieldName,
		PetscReal	t,
		Cmpnts	pos,
		Cmpnts	vel,
		PetscReal *	psi_io
	)

Updates a single particle's field based on its state and the specified field name.

This function serves as a switchboard for various particle property calculations. Given a particle's data, it computes a new value for the specified field.

Currently supported fields:

• "Psi": Calculates the particle's kinetic energy (0.5 * |v|^2).

Parameters

[in]	fieldName	The name of the field to update (e.g., "Psi").
[in]	t	The current simulation time.
[in]	pos	The particle's physical position.
[in]	vel	The particle's velocity.
[in,out]	psi_io	A pointer to the particle's current Psi value (used for accumulation if needed).

Returns

PetscErrorCode 0 on success.

Definition at line 29 of file ParticlePhysics.c.

{
    PetscFunctionBeginUser;
 
    if (strcmp(fieldName, "Psi") == 0) {
        // --- Calculate Kinetic Energy ---
        // Formula: Psi = 0.5 * (vx^2 + vy^2 + vz^2)
        *psi_io = 0.5 * (vel.x * vel.x + vel.y * vel.y + vel.z * vel.z);
 
    }
    // else if (strcmp(fieldName, "SomeOtherField") == 0) {
    //     // ... logic for another field ...
    // }
    else {
        // If the field name is not recognized, we can choose to do nothing or raise an error.
        // For now, we'll just log a warning and do nothing.
        LOG_ALLOW(GLOBAL, LOG_WARNING, "UpdateParticleField: Field name '%s' not recognized. No update performed.\n", fieldName);
    }
 
    PetscFunctionReturn(0);
}

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UpdateFieldForAllParticles()

PetscErrorCode UpdateFieldForAllParticles	(	UserCtx *	user,
		const char *	fieldName
	)

Loops over all local particles and updates a specified field.

This function orchestrates the update of a single particle field across the entire local swarm. It gets access to the necessary particle data arrays and calls the UpdateParticleField kernel for each particle.

Parameters

[in,out]	user	Pointer to the UserCtx containing the swarm and simulation context.
[in]	fieldName	The name of the field to update (e.g., "Psi").

Returns

PetscErrorCode 0 on success.

Definition at line 69 of file ParticlePhysics.c.

{
    PetscErrorCode ierr;
    DM             swarm = user->swarm;
    PetscInt       n_local;
    PetscReal      current_time = user->simCtx->ti;
 
    // Pointers to swarm data arrays
    const PetscReal *pos_arr;
    const PetscReal *vel_arr;
    PetscReal       *psi_arr; // This will be our target field array
 
    PetscFunctionBeginUser;
    PROFILE_FUNCTION_BEGIN;
 
    ierr = DMSwarmGetLocalSize(swarm, &n_local); CHKERRQ(ierr);
    if (n_local == 0) {
        PetscFunctionReturn(0); // Nothing to do on this rank
    }
 
    // Get read access to position and velocity
    ierr = DMSwarmGetField(swarm, "position", NULL, NULL, (void**)&pos_arr); CHKERRQ(ierr);
    ierr = DMSwarmGetField(swarm, "velocity", NULL, NULL, (void**)&vel_arr); CHKERRQ(ierr);
    
    // Get write access to the target field
    ierr = DMSwarmGetField(swarm, fieldName, NULL, NULL, (void**)&psi_arr); CHKERRQ(ierr);
 
    // Loop over each local particle
    for (PetscInt p = 0; p < n_local; ++p) {
        // Unpack data for the current particle
        Cmpnts current_pos = {pos_arr[3*p + 0], pos_arr[3*p + 1], pos_arr[3*p + 2]};
        Cmpnts current_vel = {vel_arr[3*p + 0], vel_arr[3*p + 1], vel_arr[3*p + 2]};
        
        // Call the kernel to calculate and update the value in the array directly.
        // We pass the address of the specific particle's entry in the psi_arr.
        ierr = UpdateParticleField(fieldName, current_time, current_pos, current_vel, &psi_arr[p]); CHKERRQ(ierr);
    }
 
    // Restore all field arrays
    ierr = DMSwarmRestoreField(swarm, "position", NULL, NULL, (void**)&pos_arr); CHKERRQ(ierr);
    ierr = DMSwarmRestoreField(swarm, "velocity", NULL, NULL, (void**)&vel_arr); CHKERRQ(ierr);
    ierr = DMSwarmRestoreField(swarm, fieldName,  NULL, NULL, (void**)&psi_arr); CHKERRQ(ierr);
 
    LOG_ALLOW(GLOBAL, LOG_INFO, "Updated particle field '%s' for all local particles.\n", fieldName);
 
    PROFILE_FUNCTION_END;
    PetscFunctionReturn(0);
}

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UpdateAllParticleFields()

PetscErrorCode UpdateAllParticleFields

(

UserCtx *

user

)

Orchestrates the update of all physical properties for particles.

This function serves as the top-level entry point for updating particle-specific physical quantities after their position and the surrounding fluid velocity are known. It calls a sequence of more specific update routines for each property.

For example, it can be configured to update:

• Particle kinetic energy (stored in "Psi")
• Particle accumulated shear stress
• Particle temperature
• etc.

Parameters

[in,out]

user

Pointer to the UserCtx containing the swarm and simulation context.

Returns

PetscErrorCode 0 on success.

Definition at line 137 of file ParticlePhysics.c.

{
    PetscErrorCode ierr;
 
    PetscFunctionBeginUser;
    PROFILE_FUNCTION_BEGIN;
 
    LOG_ALLOW(GLOBAL, LOG_INFO, "Updating all particle physical properties...\n");
 
    // --- Call updater for 'Psi' field (currently calculating Kinetic Energy) ---
    ierr = UpdateFieldForAllParticles(user, "Psi"); CHKERRQ(ierr);
 
    // --- FUTURE EXPANSION: Add calls for other fields here ---
    /*
    if (simCtx->enable_temperature_solve) {
        ierr = UpdateFieldForAllParticles(user, "Temperature"); CHKERRQ(ierr);
    }
    if (simCtx->enable_species_transport) {
        ierr = UpdateFieldForAllParticles(user, "SpeciesMassFraction"); CHKERRQ(ierr);
    }
    */
 
    LOG_ALLOW(GLOBAL, LOG_INFO, "All particle physical properties updated.\n");
    
    PROFILE_FUNCTION_END;
    PetscFunctionReturn(0);
}

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