Abstract
This study presents experimental data on the hydrodynamic features of a nonlinear solitary wave of height H0 = 2.9 cm propagating over a horizontal bed in otherwise still water depth h0 = 8.0 cm. High-speed particle image velocimetry is used to quantify the local and convective particle accelerations and pressure gradients under the solitary wave. It is found that the magnitudes of the horizontal and vertical particle local accelerations are invariably larger than their convective counterparts, highlighting the important contribution of local acceleration to the pressure gradient in a solitary wave. The dimensionless pressure gradient in the horizontal direction is favorable, zero, and adverse for time before, at, and after the wave crest passes the section of interest. The dimensionless adverse pressure gradient exhibits a maximum for the dimensionless time T[=t(g/h0)1/2, where g is the gravitational acceleration and t is the time with respect to the crest passing the section] = 1.39, at which the dimensionless local acceleration has a negative maximum. Subsequently, flow reversal takes place above the bed surface. The relationship is elucidated between flow reversal at the bed surface and the evolution of the adverse pressure gradient in the near-bed zone, where uniform horizontal/free stream velocity exists.
Highlights
Observations of the movement of a solitary wave over a long distance in a canal was first reported by Russell,1 who conducted laboratory experiments and derived an empirical formula for wave celerity
This study presents experimental data on the hydrodynamic features of a nonlinear solitary wave of height H0 = 2.9 cm propagating over a horizontal bed in otherwise still water depth h0 = 8.0 cm
The dimensionless adverse pressure gradient exhibits a maximum for the dimensionless time T[= t(g/h0)1/2, where g is the gravitational acceleration and t is the time with respect to the crest passing the section] = 1.39, at which the dimensionless local acceleration has a negative maximum
Summary
Observations of the movement of a solitary wave over a long distance in a canal was first reported by Russell, who conducted laboratory experiments and derived an empirical formula for wave celerity. Jensen et al. employed particle image velocimetry (PIV) to obtain the velocity field near the still water shoreline and analyzed the local acceleration field in a solitary wave propagating over a 1:5.38 sloping bed Their results indicated that, for a highly nonlinear solitary wave (H0/h0 = 0.663), a maximum acceleration of about 2.0g occurred behind the toe of the almost vertical front of the wave profile. Using HSPIV, Lin et al. explored the features of FSEs and velocity fields as well as accelerations and pressure gradients in the onshore and offshore flows during run-up and run-down motions of a non-breaking solitary wave (H0/h0 = 0.363) over a 1:3 sloping bed Their results showed that the local acceleration in the offshore direction ranges from zero to a negative maximum of −2.117g at the instant the projecting jet obliquely points downward before impinging upon the free surface of the run-down flow.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call