Unsteady wave pattern generation by water striders

TL;DR

This study combines experimental measurements and theoretical modeling to analyze the wave patterns generated by water striders' leg strokes, extending existing impulsive forcing theory to finite depth for better accuracy.

Contribution

It introduces an extended theoretical model that accounts for finite depth and continuous forcing, improving the match with experimental observations of water strider wave patterns.

Findings

Extended B"uhler's theory to finite depth

Accurate measurement of wave patterns using synthetic Schlieren

Improved theoretical-experimental agreement when considering continuous forcing

Abstract

We perform an experimental and theoretical study of the wave pattern generated by the leg strokes of water striders during a propulsion cycle. Using the synthetic Schlieren method, we are able to measure the dynamic response of the free surface accurately. In order to match experimental conditions, we extend B\"uhler's theory of impulsive forcing (\cite{buhler}) to finite depth. We demonstrate the improved ability of this approach to reproduce the experimental findings, once the observed continuous forcing and hence non-zero temporal and spatial extent of the leg strokes is also taken into account.