1import pandas 2import matplotlib.pyplot as plt 3import seaborn as sns 4import numpy as np 5import scipy.signal as sig 6 7 8def coeff(force, rho=1, u=1, D=1, zspan=0.2): 9 S = np.pi * D * zspan # surface area 10 return 2 * force / (rho * u**2 * S) 11 12 13def shedding_period(df): 14 sample = df[df["Time"] > 70] # once the initial transient has passed 15 peaks, _ = sig.find_peaks(sample["ForceY"]) 16 period = np.diff(sample["Time"].iloc[peaks]) 17 return period.mean() 18 19 20df = pandas.read_csv("force.csv") 21df["Drag Coefficient"] = coeff(df["ForceX"]) 22df["Lift Coefficient"] = coeff(df["ForceY"]) 23period = shedding_period(df) 24 25sns.set_theme(style="ticks") 26palette = sns.color_palette() 27fig, ax_drag = plt.subplots() 28ax_lift = ax_drag.twinx() 29 30sns.lineplot(data=df, x="Time", y="Drag Coefficient", ax=ax_drag, color=palette[0]) 31sns.lineplot(data=df, x="Time", y="Lift Coefficient", ax=ax_lift, color=palette[1]) 32ax_drag.set_title(f"Shedding period {period}") 33ax_drag.set_ylim(0.41, 0.49) 34ax_drag.tick_params(axis="y", colors=palette[0]) 35ax_drag.yaxis.label.set_color(palette[0]) 36ax_lift.tick_params(axis="y", colors=palette[1]) 37ax_lift.yaxis.label.set_color(palette[1]) 38 39# plt.savefig("vortexshedding.svg") 40plt.show() 41