Asynchronous shedding phenomena due to moving in-line double pressure sources on deep water

Moving in-line double pressure sources move horizontally over the surface of deep water with speeds near the minimum phase speed c_min=23cm/s of gravity-capillary waves on deep water. Three different periodic shedding phenomena of 3-D depressions are observed according to the pressure-source speed near c_min; synchronous (in-phase) symmetric shedding of 3-D depressions behind each moving pressure source, asynchronous (out-of-phase) symmetric shedding of 3-D depressions behind each moving pressure source, and symmetric shedding of 3-D depressions behind the moving front pressure source along with the steady ‘V’-shaped wave pattern behind the moving rear pressure source. These experimental observations are compared with numerical results based on a model equation that admits gravity–capillary wave solutions near c_min. They agree with each other very well.