I am working on simulating a simple pendulum with present drag forces. My task is to use numerical methods (I am using Verlet integrator) to estimate the angle as a function of time, as well as the angular velocity and acceleration.
I am supposed to track the motion of the pendulum for 24s to measure the angle and angular velocity evolution and make a phase space diagram of these.
Even for a dt of 0.001, at 0.1 seconds I observe this:
It is worth noting that at the end of the simulation for this case, the steps taken are about 100,000.
I know that error-build up must be an issue here.
My question is, do I have to find another numerical method to estimate this oscillation that can handle this task? Or am I not using Verlet correctly?