Techniques for measuring bulge-scar pattern of free surface deformation and related velocity distribution in shallow water flow over a bump
Abstract
One of the unsteady features of shallow water free surface waves over a bump is the bulge-scar pattern of the free surface deformation. An imaging technique is developed to measure the duration, displacement and size of the bulge-scar pattern from the bump top to the primary wave crest. A unique configuration of particle image velocimetry is used to measure the velocity distribution under the visualized free surface bulge at the primary wave trough. Test results indicate that the bulge-scar pattern of the free surface deformation is related to a stream-wise vortex pair in the secondary flow over the bump. The new measurement techniques may work together with the conventional measurement techniques to obtain a complete database for the shallow water free surface instability over the bump.
- Publication:
-
Experiments in Fluids
- Pub Date:
- April 2014
- DOI:
- 10.1007/s00348-014-1721-9
- Bibcode:
- 2014ExFl...55.1721G
- Keywords:
-
- Free Surface;
- Particle Image Velocimetry;
- Vortex Pair;
- Free Surface Elevation;
- Laser Light Sheet