Simulations have been carried out for the flow through a throttle valve to determine the flow mechanisms for various blade angles. In all cases, the time-dependence of the flow had to be accounted for. From this the relationship between blade angle and frequency of oscillation has been found. Comparisons have also been made between solutions with tetrahedral unstructured meshes and hexahedral structured meshes. Finally, it has been found that adding a breather pipe to the throttle removes the oscillation entirely.