""" Utilities for the OpenFOAM simulation. Also look into /openfoam and oclerc/improved_car_dataset/Preprocessing """ import os, os.path import shutil import re import trimesh import numpy as np RE_FLOAT = '-?[0-9]+\.?[0-9]*' # signed float RE_VECTOR = f'\(\s*{RE_FLOAT}\s*{RE_FLOAT}\s*{RE_FLOAT}\s*\)' # 3d vector of signed floats CONFIG_FILE = "include/config" CAR_STL_FILE = "constant/triSurface/car.stl" #################################################################################################### # Simulation setup #################################################################################################### def find_highest_point(mesh, epsilon=0.05): """Find point close to max height and the further front.""" height = mesh.bounds[1, 2] close_p = mesh.vertices[:,2] > height - epsilon verts = mesh.vertices[close_p] return verts[verts[:,0].argmin()] def get_vr4(mesh): # From DRIVAER template _vr4_min, _vr4_max = np.array([3.2, -1., -0.3]), np.array([6.2, 1.0, 1.0]) vr4_min, vr4_max = _vr4_min.copy(), _vr4_max.copy() # x: start on highest point, then end on offset to the car vr4_min[0] = find_highest_point(mesh)[0] x_offset = 2.395022 # from DRIVAER vr4_max[0] = mesh.bounds[1,0] + x_offset # y: resize based on ratio to DRIVAER ratio_y = mesh.extents[1] / 2.02998 # from DRIVAER vr4_y = (_vr4_max[1] - _vr4_min[1]) * ratio_y vr4_min[1], vr4_max[1] = -vr4_y / 2, vr4_y / 2 # z: to car height vr4_max[2] = mesh.bounds[1,2] return vr4_min, vr4_max def get_vr3(mesh, vr4): # From DRIVAER template _vr3_min, _vr3_max = np.array([2.5, -1.5, -0.3]), np.array([7.5, 1.5, 1.4]) vr3_min, vr3_max = _vr3_min.copy(), _vr3_max.copy() # x: start on highest point, then constant offset to vr4 vr3_min[0] = find_highest_point(mesh)[0] x_offset = 1.3 # from DRIVAER vr3_max[0] = vr4[1][0] + x_offset # y: constant offset to vr4 y_offset = 0.5 vr3_min[1] = vr4[0][1] - y_offset vr3_max[1] = vr4[1][1] + y_offset # z: height of car + constant offset z_offset = 0.300101 # from DRIVAER vr3_max[2] = mesh.bounds[1,2] + z_offset return vr3_min, vr3_max def get_vr2(mesh, vr3): # From DRIVAER template _vr2_min, _vr2_max = np.array([-2.0, -2.0, -0.3]), np.array([9.0, 2.0, 1.7]) vr2_min, vr2_max = _vr2_min.copy(), _vr2_max.copy() # x: same offset to front and to vr3 front_x_offset = 1.192151 # between DRIVAER and vr2 back_x_offset = 1.5 # between vr3 and 2 vr2_min[0] = mesh.bounds[0,0] - front_x_offset vr2_max[0] = vr3[1][0] + back_x_offset # y: constant offset to vr3 y_offset = 0.5 vr2_min[1] = vr3[0][1] - y_offset vr2_max[1] = vr3[1][1] + y_offset # z: constant offset to vr3 z_offset = 0.3 vr2_max[2] = vr3[1][2] + z_offset return vr2_min, vr2_max def get_vr1(mesh): # From DRIVAER template _vr1_min, _vr1_max = np.array([-7.5, -3.0, -0.3]), np.array([25.0, 3.0, 3.7]) vr1_min, vr1_max = _vr1_min.copy(), _vr1_max.copy() # Fixed return vr1_min, vr1_max def get_all_vr(mesh): vr4_min, vr4_max = get_vr4(mesh) vr3_min, vr3_max = get_vr3(mesh, (vr4_min, vr4_max)) vr2_min, vr2_max = get_vr2(mesh, (vr3_min, vr3_max)) vr1_min, vr1_max = get_vr1(mesh) return (vr4_min, vr4_max), (vr3_min, vr3_max), (vr2_min, vr2_max), (vr1_min, vr1_max) def find_Aref(mesh, ray_per_dim=512): """Approximate frontal area by intersecting rays.""" y_min, y_max = mesh.bounds[:,1] z_min, z_max = mesh.bounds[:,2] yz_area = (y_max - y_min) * (z_max - z_min) YZ = np.stack(np.meshgrid( np.linspace(y_min, y_max, ray_per_dim), np.linspace(z_min, z_max, ray_per_dim), ), axis=-1).reshape(-1, 2) YZ = np.concatenate([np.full_like(YZ[:,0:1], -2), YZ], axis=1) intersections = mesh.ray.intersects_any(YZ, [[1,0,0]]* len(YZ)) return yz_area * intersections.mean() def vector2str(vector): return " ".join(["("] + [f"{x:.2f}" for x in vector]+ [")"]) def edit_config(configpath, aref, vr1_min, vr1_max, vr2_min, vr2_max, vr3_min, vr3_max, vr4_min, vr4_max): with open(configpath, 'r') as f: content = f.read() # Automatic edition of Aref content = re.sub(f'Aref\s*{RE_FLOAT}\s*;', f'Aref {aref:.6f};', content) # Automatic edition of vri's content = re.sub(f'vr1_min\s*{RE_VECTOR}\s*;', f'vr1_min {vector2str(vr1_min)};', content) content = re.sub(f'vr1_max\s*{RE_VECTOR}\s*;', f'vr1_max {vector2str(vr1_max)};', content) content = re.sub(f'vr2_min\s*{RE_VECTOR}\s*;', f'vr2_min {vector2str(vr2_min)};', content) content = re.sub(f'vr2_max\s*{RE_VECTOR}\s*;', f'vr2_max {vector2str(vr2_max)};', content) content = re.sub(f'vr3_min\s*{RE_VECTOR}\s*;', f'vr3_min {vector2str(vr3_min)};', content) content = re.sub(f'vr3_max\s*{RE_VECTOR}\s*;', f'vr3_max {vector2str(vr3_max)};', content) content = re.sub(f'vr4_min\s*{RE_VECTOR}\s*;', f'vr4_min {vector2str(vr4_min)};', content) content = re.sub(f'vr4_max\s*{RE_VECTOR}\s*;', f'vr4_max {vector2str(vr4_max)};', content) with open(configpath, 'w') as f: f.write(content) def copy_template(dst, src="/mnt/cvlab/scratch/cvlab/home/hantzhan/cfd_workflow/template/"): shutil.copytree(src, dst) def setup_simulation(simdir, aref_ray=512): """Correctly transform the car and compute the config parameters.""" # 1. Verify the existence of a mesh if not os.path.isfile(os.path.join(simdir, CAR_STL_FILE)): print(f"File does not exist! ({simdir}) Skipping...") return car = trimesh.load(os.path.join(simdir, CAR_STL_FILE)) # 2. Frontal area aref_pred = find_Aref(car, ray_per_dim=aref_ray) # 3. Refinement regions (vr4_min, vr4_max), (vr3_min, vr3_max), (vr2_min, vr2_max), (vr1_min, vr1_max) = get_all_vr(car) # Edit the config file edit_config(os.path.join(simdir, "include/config"), aref_pred, vr1_min, vr1_max, vr2_min, vr2_max, vr3_min, vr3_max, vr4_min, vr4_max) #################################################################################################### # Utilities #################################################################################################### def get_Cd_sim(simdir, itercheck=2500, average=1000, load_always=False): """ Get the drag coefficient from the simulation directory. itercheck: int (optional) If given, will verify if the max iteration is the given int. average: int If not None, will return the average Cd over the last `average` iters. load_always: bool If True, will load the data even if the simulation is not finished. If return value is negative, then an error has been raised: -1: Unknown error. -2: Experiment is not finished. -3: Problem in loading the force coeff data. """ try: if not os.path.isdir(os.path.join(simdir, "postProcessing")): print(f"{simdir} might not be finished (no 'postProcessing' folder).") return -2 # Get data in tabular form try: data = [] with open(os.path.join(simdir, "postProcessing/car/0/forceCoeffs.dat")) as file: for line in file: if line[0] == '#': # The last commented line should correspond to column names names = line[1:].split() else: data.append(line.split()) data = np.array(data).astype(float) if itercheck is not None and len(data)-1 != itercheck: print(f"WARNING ({simdir}): iteration number is incorrect ({len(data)-1}!={itercheck})!") if not load_always: return -2 except ValueError as err: print(f"Cannot load data from {simdir}: {err}") return -3 # Extract the drag coeff (optionally average over the last iters) col = names.index('Cd') if 'Cd' in names else 2 if average is not None: cd = data[-average:, col].mean() else: cd = data[:, col] return cd except Exception as err: print(f"Unknown exception for {simdir}: {err}") return -1