15 pendula solution

pen_15.py

from numpy import linspace,array,outer,sqrt,cos,pi
from matplotlib import pyplot as plt
from seaborn import color_palette

n=15
L=array([0.625+0.05/2*j for j in range(n)]) # m
omega=sqrt(9.81/L) # 1/s

n_range=[10,20,30,40,50,60,70,80,90,100,110,120,130,140,150,160]
fig,ax_list=plt.subplots(len(n_range),1,figsize=(15,10),constrained_layout=True)

nmin=0
for i,nmax in enumerate(n_range):
    t=linspace(nmin*2*pi/(max(omega)),nmax*2*pi/(max(omega)),5000)
    theta_0=1/4*pi
    accelerate=8
    theta=theta_0*cos(accelerate*outer(omega,t).T)

    for j in range(n):
        ax_list[i].plot(t,theta[:,j],label='L={:g} m'.format(L[j]),color=color_palette('viridis',n)[j])

    nmin=nmax
    ax_list[i].set_ylabel(r'$\theta$')
ax_list[-1].set_xlabel(r'$t$ / s')
ax_list[-1].legend(ncols=5,loc='upper center',bbox_to_anchor=[0.5,-0.05])
plt.show(block=False)