Wave generation instrumentation in hydraulic models

Abstract

Hydraulic scale models are used to study the effects of wave and tidal action at particular locations or in experimental basins. For example, the effects of wave action on ships anchored in a harbor during different stages of harbor renovation can be studied in a scale model to determine what to expect in the prototype. Based on test results, the construction work may be redirected to minimize resonant conditions and the resulting wave amplification. Similarly, scale models are used to test the effects of storms and other abnormal wave conditions on land structures, coastal erosion, ships, and moorings. A directional spectral wave generator (DSWG) can produce realistic waves at a variety of incident angles from a fixed position through sophisticated control instrumentation (hardware and software) allowing tests to be conducted more quickly and more economically. Hardware includes the wave generator, signal conditioning, and transducers. The wave generators used are purchased from commercial vendors and are designed to meet the unique specifications for a particular type of model study. U. S. Army Engineer Research and Development Center Waterways Experiment Station (ERDCWES) has a number of single paddle generators and one 60-paddle DSWG, used in flumes and wave basins. A second DSWG is currently being procured. Signal conditioning and transducers are a combination of commercially available hardware and hardware designed and constructed at ERDCWES. The transducers include wave gages and other sensors with associated electronics for signal conditioning and automated calibration. Software was written by ERDCWES engineers to control the wave and tidal action in the models to reproduce the desired test conditions.