I have carried out a CFD simulation (with finite volume method) to investigate the unsteady force enforced to the vehicle body. The horizontal tail keeps flapping in sinusoidal function. As a result, the force coefficient should be also in sinusoidal form.
And then, I plot the
force coefficient. It meets my expection, i.e. with a sinusoidal form. But the numerical result seems not smooth. What are the reasons to cause this phenomenon?