We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
非线性波作用下潜堤周围的流体分离与涡流结构.
- Authors
蒋学炼; 刘 畅; 赵 悦; 杨伟超; 柳淑学; 朱福明
- Abstract
Flow separation and vortical dynamics generated by second-order Stokes waves propagating over a submerged rectangular breakwater supported on a rubble mound were investigated using particle image velocimetry (PIV) technology and numerical model based on Reynolds–averaged-Navier–Stokes equations (RANS). Experimental wave surfaces show nonlinear deformation before and after the structure. The asymmetry and skewness of the weatherside wave profile are –0.21 and 0.04, respectively, which indicates a steep front face and gentle rear face. The asymmetry and skewness of the leeside wave profile are –0.39 and 0.99, respectively, which indicates more significant lack of symmetry relative to vertical and horizontal axes. Phase-averaged velocity and vortex fields calculated from PIV data show that clockwise and counterclockwise vortices are generated periodically on the weatherside and leeside of the structure. However, these vortices are not fully developed. The subsequent flow reversal moves the vortices towards the free surface or the structure to make them dissipated. The weatherside vortex pair is confined within a relatively narrow region of about 0.5 times Keulegan–Carpenter number from the weatherside of the structure, which implies smaller wave energy dissipation. Meanwhile, the leeside vortex pair is confined within a relatively wide region of about 1.0 times Keulegan–Carpenter number from the leeside of the structure, which indicates greater dissipation of wave energy. In addition, a small circulation system is found above the up- stream shoulder of the rubble mound and its movement is confined within two times the unperturbed wave particle trajectory, which may lead to local scouring. A numerical wave flume was established based on RANS–VOF mode and then verified by experimental results. The applicability of different wave-making methods and the effect of energy dissipation by sponge layer were analyzed. The RANS–VOF model was then used to further study the flow separation of shear boundary layers. Numerical results show that the supply of vorticity mainly comes from the shear boundary layers at the surface of the structure. The adverse vorticity in the shear boundary layers is induced by the adverse pressure gradient imposed by the movement of the vortices previously shed from the structure. The generation, shedding, stretching, advection and dissipation of vortices is expected to significantly change the local flow around submerged structures and hence cause local scour as well as additional loading. Therefore, the effect of the complex flow induced by vortices should be taken into account in engineering design.
- Publication
Advanced Engineering Science / Gongcheng Kexue Yu Jishu, 2021, Vol 53, Issue 5, p10
- ISSN
2096-3246
- Publication type
Article
- DOI
10.15961/j.jsuese.202000991