we_collect/luftwiderstand.py

from matplotlib import pyplot as plot
import numpy as np
temperatures = []

# Standard-Atmosphärendruck [Pa]
g_p0 = 101325

# spezifischen Gaskonstante R_S = R/M = 287,058   J/(kg*K) für trockene Luft
g_RS = 287.54

# CW-Wert und Stirnfläche
c_val_id3 = 0.267
area_id3 = 2.360	# m^2

car_list = [
	{
		"car": "VW id.3",
		"cw": 0.267,
		"area": 2.360
	},
	{
		"car": "Tesla Model Y LR AWD",
		"cw": 0.23,
		"area": 2.518
	},
	{
		"car": "Tesla Model 3 LR AWD",
		"cw": 0.23,
		"area": 2.220
	},
	{
		"car": "Polestar 2",
		"cw": 0.278,
		"area": 2.480
	},
	{
		"car": "Renault Zoe",
		"cw": 0.33,
		"area": 2.27
	},
	{
		"car": "Hyundai Kona Elektro",
		"cw": 0.29,
		"area": 2.37
	},
	{
		"car": "Hyundai Ioniq Elektro",
		"cw": 0.24,
		"area": 2.22
	}
]

temp_list = [-20, -10, 0, 10, 20, 30]
vel_list = [20, 40, 60, 80, 100, 120, 130, 140, 160]


# rho: [kg/m3]
def rho(temperature_degc: float, p_pa: float =g_p0):
	return p_pa/(g_RS*(temperature_degc + 273.15))

# Force : N = kg·m·s2
def fd(rho: float, velocity_kmh: float, c_val: float, area: float):
	vel = velocity_kmh / 3.6
	cwa = c_val * area
	res = 0.5*rho*vel*vel*cwa
	return res

def plot_1(fd_reference):
	temps_list_leg = [f"{t}°C" for t in temp_list]
	plot.figure()
	for temp_degc in temp_list:
		rho_t = rho(temp_degc)
		y_fd = []
		for vel_kmh in vel_list:
			fd_t = (fd(rho_t, vel_kmh, c_val_id3, area_id3)/fd_reference - 1) * 100
			y_fd.append(fd_t)

		plot.plot(vel_list, y_fd)

	plot.title("Luftwiderstand vs Geschwindigkeit")
	plot.ylabel("Luftwiderstand [%]")
	plot.xlabel("Geschwindigkeit [km/h]")
	plot.legend(temps_list_leg)
	plot.grid()

def plot_2(temp=20):
	''' Fd vs. velocity, param: car '''
	# [kmh]
	car_list_leg = [f"{t['car']}" for t in car_list]
	rho_t = rho(temp)
	reference = fd(rho_t, 100, c_val_id3, area_id3)
	plot.figure()
	for car in car_list:
		y_fd = []
		for vel_kmh in vel_list:
			fd_t = (fd(rho_t, vel_kmh, car['cw'], car['area'])/reference - 1) * 100
			y_fd.append(fd_t)

		plot.plot(vel_list, y_fd)

	plot.ylabel("Luftwiderstand ID.3 [%]")
	plot.xlabel("Geschwindigkeit [km/h]")
	plot.title(f"Luftwiderstand vs Geschwindigkeit, Temperature {temp}°C")
	plot.legend(car_list_leg)
	plot.grid()

def plot_3(y_fd, y_pwr, temp=20):
	car_list_leg = [f"{t['car']}" for t in car_list]
	fig, ax1 = plot.subplots()
	ax1.plot(vel_list, y_fd)
	ax1.set_ylabel("Luftwiderstand [N]")
	ax1.set_xlabel("Geschwindigkeit [km/h]")
	ax1.set_title(f"Luftwiderstand vs Geschwindigkeit, Temperature {temp}°C")
	ax1.legend(car_list_leg)
	ax2 = ax1.twinx()
	ax2.set_ylabel("Antriebsleistung [kW]", color='tab:red')
	ax2.plot(vel_list, y_pwr, color='tab:red')
	ax2.tick_params(axis='y', labelcolor='tab:red')
	ax1.grid()

def plot_4(y_fd, y_energy, temp=20):
	car_list_leg = [f"{t['car']}" for t in car_list]
	fig, ax1 = plot.subplots()
	ax1.plot(vel_list, y_fd)
	ax1.set_ylabel("Luftwiderstand [N]")
	ax1.set_xlabel("Geschwindigkeit [km/h]")
	ax1.set_title(f"Luftwiderstand vs Geschwindigkeit, Temperature {temp}°C")
	ax1.legend(car_list_leg)
	ax2 = ax1.twinx()
	ax2.set_ylabel("Antriebsenergie [kWh/100km]", color='tab:red')
	ax2.plot(vel_list, y_energy, color='tab:red')
	ax2.tick_params(axis='y', labelcolor='tab:red')
	ax1.grid()
	plot.show()

def main() -> None:
	# Fd vs. velocity, param: temperature
	reference = fd(rho(20), 100, c_val_id3, area_id3)
	temp_ref = 20

	# Luftwiderstand [%] vs. Geschwindigkeit [kmh], Param: Temperatur
	plot_1(reference)

	# Luftwiderstand [%] vs. Geschwindigkeit [kmh] at 20°C, Param: Car Model
	plot_2(temp_ref)

	y_fd = []
	y_pwr = []
	y_energy = []
	for vel_kmh in vel_list:
		fd_t = fd(rho(temp_ref), vel_kmh, c_val_id3, area_id3)
		y_fd.append(fd_t)
		y_pwr.append(fd_t*vel_kmh/1000/3.6)
		y_energy.append(fd_t*vel_kmh/1000/3.6*100/vel_kmh)

	# Luftwiderstand [N] / Antriebsleistung [kW] vs. Geschwindigkeit [kmh], Param: Temp
	plot_3(y_fd, y_pwr, temp_ref)

	# Luftwiderstand [N] / Antriebsenergie [kWh/100km] vs. Geschwindigkeit [kmh], Param: Temp
	plot_4(y_fd, y_energy, temp_ref)



if __name__ == '__main__':
	main()