Chenghao Xu’s scientific contributions

Inspired by the curtain-wall type breakwater, this paper introduced a reversed L type breakwater-WEC structure which is a rectangular floating breakwater with a vertical curtain wall restrained in piles. To present the performance of the new system, a numerical model based on N–S equations is introduced and validated. A numerical study is carried out to illustrate the factors on the hydrodynamic properties and structure loads of the breakwater-WEC, including the PTO damping force, the wave frequency, draft, and height of the curtain wall. It is found that its performance gets enhanced with a higher curtain wall with the expense of greater structure loads. The sensitivity analysis found that the hydrodynamic performance is sensitive to the draft and PTO damping force while the height of the curtain wall has the most influence on the restraining moment. The smaller draft gives larger capture ratio width (CWR) but slight larger transmission coefficient Ct, as well as smaller wave forces and larger wave moment. The CWR increases firstly and decreases as a function of PTO damping force while Ct shows a reverse trend. Therefore, with proper configuration, the breakwater-WEC system can achieve a satisfied level with the CWR>40% and Ct < 0.35.

The present study describes a numerical investigation on the hydrodynamic characteristics of the impinging and overtopping by solitary waves on an emerged impermeable trapezoidal seawall on a sloping beach. A flow solver of Navier-Stokes equations is employed with the constrained interpolation profile method and a volume-of-fluid type method to capture the strong nonlinear free surface. Three typical solitary waves are simulated to validate the capability of the numerical model. A favorable agreement between experimental and numerical results reveals that this model can reproduce the nonlinear hydrodynamic features of solitary wave impinging and overtopping involving vortex, breaking and impacting. Furthermore, parametric studies are conducted by numerical modeling to examine the effects of wave parameters including water level and wave nonlinearity and leeward slope ratio of the seawall on hydrodynamic stability including sliding and overturning stability and erosion potential. Vorticity and pressure fields are exhibited to show the dynamic properties of flow separation, air entrainment and breaking. It is found that the wave parameters and leeward slope ration influence the hydrodynamic stability of the seawall and erosion of the leeward slope in a different way.