Performance of a Tilt Current Meter in the Surf Zone

Tilt Current Meters (TCM’s) are relatively simple and inexpensive instruments for measuring currents in rivers and inthe sea. Their low cost and easy deployment means that a relatively large number of TCM’s can be deployed comparedto more conventional current meters such as Acoustic Doppler Velocimeters (ADV’s) or Acoustic Doppler CurrentProfiler (ADCP’s). Although, the accuracy of the individual measurements may not be as good as conventional currentmeters, the possibility of deploying many instruments is a great advantage when studying spatial variations in flows.This is especially the case when data is later used for comparison with numerical models whose results are alsoassociated with considerable uncertainty. Previous studies have mainly considered steady current or tidal flows inwhich velocities were relatively low and the importance of waves limited. The presence of waves adds a number ofimportant challenges to the measurements as the hydrodynamic forcing changes and the oscillations of the TCM cannotnecessarily be averaged out as for a steady current. This study addresses some of these challenges by analyzing theperformance of a TCM in the surf zone where wave orbital motion is dominant.