Abstract
Large-eddy simulation (LES) with dynamic one-equation subgrid-scale stress model was utilized to study the characteristics of turbulent flow over sea-surface generalized as two-dimensional wavy wall with different wave steepness. The statistical characteristics of turbulent field and pressure distribution were presented in detail. The simulation results showed that the separation zones induce stronger convection as the wave steepness increases. Reynolds shear stress near the wall boundary showed positive correlation with the wave steepness, while in the outer region, time-averaged turbulent fields seemed to be insensitive with the wall boundary. The equivalent velocity profiles obtained from the spatial averaging of the time-averaged velocity indicated that lower velocity occurred as the increase of wave steepness due to the increased pressure-induced form drag. The vortex structures were also visualized and showed vertically-bent characteristics which induced negative Reynolds shear stress at the stoss side as the increase of wave steepness that is equivalent to the effect of wave age.
Highlights
A large variety of dynamic processes in nature such as atmospheric flow over topography, current flow over seabed or airflow over water waves happen naturally (Fernando, 2010)
This study presents a large-eddy simulation of turbulent flow over wavy wall with different wave steepness
As shown in figure 1(c1)-(c4), the turbulent kinetic energy shows high correlation with the ak, and the region of higher turbulent level corresponds to the separation zones, revealing the relation between turbulent level with strong convection
Summary
A large variety of dynamic processes in nature such as atmospheric flow over topography, current flow over seabed or airflow over water waves happen naturally (Fernando, 2010). A large variety of experiments could be conducted to obtain the turbulent fields (Hudson, Dykhno, and Hanratty, 1996, Nakagawa, and Hanratty, 2001, Günther, and von Rohr, 2003) These studies gave detailed description of the flow characteristics, how the vortex structures impact the turbulent fields with different wave steepness (or the ratio of amplitude to wavelength) was not discussed in detail. Different from the flat wall boundary layer, Hamed et al (2015), by experiments, found that negative Reynolds shear stress occurred at stoss side when flowing over wavy wall boundary and it is the reason by using cartesian coordinate system (Hudson, Dykhno, and Hanratty, 1996, Cherukat, Hanratty, and Mclaughlin, 1998) While another explanation by Yang and Shen (2009) was that quasi-streamwise vortices at stoss side with ejection events induces negative Reynolds shear stress. The vortex structures were extracted to explain the impact on high-order statistics of turbulent fields
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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
