Debug wall collisions and particle state writing

[danieljvickers]

Description

Branch created to debug some issues I was having with particles not colliding with one of the domain boundaries when slip wall was used. The solution wound up being that the variable populating slip wall BC at the top of the boundary was not populated on the GPU. Updates have been made.

While I was in the code, I also noticed that ib_state_wrt will not trigger in post-process is all IBs are from particle_clouds. This is because when it checks for the number of IBs to create the array, it was not including cloud particles, and therefore generated 0-lengthed arrays. I added the particle cloud count to this check, allowing it to store more IB information for output.

Type of change (delete unused ones)

• Bug fix

Testing

I generated a 2D, 2000 particle case as:

import json
import math

# 2D shock wave interacting with a bed of 20 free-floating circular particles.

gam_a = 1.4

# Shock parameters (Mach 1.5)
mach_number = 1.5
pre_shock_pressure = 1
pre_shock_density = 1.4
pre_shock_speed = 0.0
post_shock_pressure = 2.4583
post_shock_density = 2.6069
post_shock_speed = 0.6944

domain_size = 4.0
wave_front = -1.5

total_time = 2.5
num_time_steps = 4000
dt = float(total_time / num_time_steps)
num_saves = 400
steps_to_save = int(num_time_steps / num_saves)

# Soft-sphere collision parameters (from 3D_mibm_sphere_head_on_collision)
collision_time = 20.0 * dt

# Particle bed parameters
bed_x = 0.25
bed_y = 0.0
bed_lx = 3.0
bed_ly = 3.92
particle_radius = 0.02
particle_mass = 0.2
particle_min_spacing = 0.005

print(
    json.dumps(
        {
            # Logistics
            "run_time_info": "T",
            # Computational Domain Parameters
            "x_domain%beg": -domain_size * 0.5,
            "x_domain%end": domain_size * 0.5,
            "y_domain%beg": -domain_size * 0.5,
            "y_domain%end": domain_size * 0.5,
            "cyl_coord": "F",
            "m": 1024,
            "n": 1024,
            "p": 0,
            "dt": dt,
            "t_step_start": 0,
            "t_step_stop": num_time_steps,
            "t_step_save": steps_to_save,
            # Simulation Algorithm Parameters
            "num_patches": 2,
            "model_eqns": 2,
            "alt_soundspeed": "F",
            "num_fluids": 1,
            "mpp_lim": "F",
            "mixture_err": "T",
            "time_stepper": 3,
            "weno_order": 5,
            "weno_eps": 1.0e-16,
            "weno_Re_flux": "T",
            "weno_avg": "T",
            "avg_state": 2,
            "mapped_weno": "T",
            "null_weights": "F",
            "mp_weno": "T",
            "riemann_solver": 2,
            "wave_speeds": 1,
            "fd_order": 2,
            "bc_x%beg": -17,
            "bc_x%end": -8,
            "bc_y%beg": -15,
            "bc_y%end": -15,
            # Immersed boundaries — all circles come from the particle bed
            "ib": "T",
            "num_ibs": 0,
            "viscous": "T",
            # Collision model (soft-sphere, from 3D_mibm_sphere_head_on_collision)
            "collision_model": 1,
            "coefficient_of_restitution": 0.9,
            "collision_time": collision_time,
            "ib_coefficient_of_friction": 0.1,
            # Particle bed: 20 free-floating circles placed randomly in region
            "num_particle_clouds": 1,
            "particle_cloud(1)%x_centroid": bed_x,
            "particle_cloud(1)%y_centroid": bed_y,
            "particle_cloud(1)%z_centroid": 0.0,
            "particle_cloud(1)%length_x": bed_lx,
            "particle_cloud(1)%length_y": bed_ly,
            "particle_cloud(1)%length_z": 0.0,
            "particle_cloud(1)%num_particles": 2000,
            "particle_cloud(1)%radius": particle_radius,
            "particle_cloud(1)%mass": particle_mass,
            "particle_cloud(1)%min_spacing": particle_min_spacing,
            "particle_cloud(1)%moving_ibm": 2,
            "particle_cloud(1)%seed": 42,
            "particle_cloud(1)%packing_method": 1,
            # Output
            "format": 1,
            "precision": 2,
            "prim_vars_wrt": "T",
            "E_wrt": "T",
            "ib_state_wrt": "T",
            "parallel_io": "T",
            # IC Patch 1: post-shock region (left of wave front)
            "patch_icpp(1)%geometry": 3,
            "patch_icpp(1)%x_centroid": 0.5 * wave_front - 0.25 * domain_size,
            "patch_icpp(1)%y_centroid": 0.0,
            "patch_icpp(1)%length_x": 0.5 * domain_size + wave_front,
            "patch_icpp(1)%length_y": domain_size,
            "patch_icpp(1)%vel(1)": post_shock_speed,
            "patch_icpp(1)%vel(2)": 0.0,
            "patch_icpp(1)%pres": post_shock_pressure,
            "patch_icpp(1)%alpha_rho(1)": post_shock_density,
            "patch_icpp(1)%alpha(1)": 1.0,
            # IC Patch 2: pre-shock region (right of wave front)
            "patch_icpp(2)%geometry": 3,
            "patch_icpp(2)%x_centroid": 0.5 * wave_front + 0.25 * domain_size,
            "patch_icpp(2)%y_centroid": 0.0,
            "patch_icpp(2)%length_x": 0.5 * domain_size - wave_front,
            "patch_icpp(2)%length_y": domain_size,
            "patch_icpp(2)%vel(1)": pre_shock_speed,
            "patch_icpp(2)%vel(2)": 0.0,
            "patch_icpp(2)%pres": pre_shock_pressure,
            "patch_icpp(2)%alpha_rho(1)": pre_shock_density,
            "patch_icpp(2)%alpha(1)": 1.0,
            # Fluid properties: air
            "fluid_pp(1)%gamma": 1.0 / (gam_a - 1.0),
            "fluid_pp(1)%pi_inf": 0,
            "fluid_pp(1)%Re(1)": 2500000,
        }
    )
)

This case was run on an RTX 2080 Super with NVHPC/23.11

Checklist

Check these like this [x] to indicate which of the below applies.

• [] I added or updated tests for new behavior
• I updated documentation if user-facing behavior changed

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 61.65%. Comparing base (55fb1b1) to head (1db3c40).
⚠️ Report is 9 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1745      +/-   ##
==========================================
+ Coverage   61.59%   61.65%   +0.05%     
==========================================
  Files          84       84              
  Lines       21493    21543      +50     
  Branches     3176     3180       +4     
==========================================
+ Hits        13239    13282      +43     
- Misses       6078     6082       +4     
- Partials     2176     2179       +3     

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