Comparison of experimental and numerical ship wakes using time-frequency analysis

Ships travelling steadily cause three-dimensional V-shaped wave patterns which can be observed far away from the sailing line of the ship. Since it is difficult to accurately measure these waves across large domains, we are exploring the quantity of information that can be gathered from recording the surface elevation at single point in space as the ship travels by. The approach used involves time-frequency analysis with spectrograms. We compare experimental data from ship model basin experiments using aWigley hull with numerical simulations from a thin-ship model and show that only the far-field component of the numerical solution is necessary for generating spectrograms from signals gathered three ship lengths from the sailing line of the ship. This result is useful since it is much easier to simulate the far field from the thin-ship model than the near field. The spectrograms constructed using the thin-ship model and the experimental results are shown to match well.