A nonlinear short-wave-averaged (surf beat) model is presented. The model is based on that of Roelvink (1993), but the numerical techniques used in the solution are based on the so-called weighted-averaged flux (WAF) ...A nonlinear short-wave-averaged (surf beat) model is presented. The model is based on that of Roelvink (1993), but the numerical techniques used in the solution are based on the so-called weighted-averaged flux (WAF) method (eg Watson et al., 1992), with time-operator splitting used for the treatment of some of the source terms. This method allows a small number of computational points to be used, and is particularly efficient in modelling breaking long waves. The short-wave (or primary-wave) energy equation is solved using a more traditional Lax-Wendroff technique. Results of validation indicate that the model performs satisfactorily in most respects.展开更多
As an important hydrodynamic phenomenon in the nearshore zone, the cross-shore surf beat is numerically studied in this paper with a fully nonlinear Boussinesq-type model, which resolves the primary wave motion as wel...As an important hydrodynamic phenomenon in the nearshore zone, the cross-shore surf beat is numerically studied in this paper with a fully nonlinear Boussinesq-type model, which resolves the primary wave motion as well as the long waves. Compared with the classical Boussinesq equations, the equations adopted here allow for improved linear dispersion characteristics. Wave breaking and run-up in the swash zone are included in the numerical model. Mutual interactions between short waves and long waves are inherent in the model. The numerical study of long waves is based on bichromatic wave groups with a wide range of mean frequencies, group frequencies and modulation rates. The cross-shore variation in the amplitudes of short waves and long waves is investigated. The model results are compared with laboratory experiments from the literature and good agreement is found.展开更多
The generation of low frequency waves by a single or double wave groups incident upon two Plane beaches with the slope of 1/40 and 1/100 is investigated experimentally and numerically. A new type of wave maker signal ...The generation of low frequency waves by a single or double wave groups incident upon two Plane beaches with the slope of 1/40 and 1/100 is investigated experimentally and numerically. A new type of wave maker signal is used to generate the groups, allowing the bound long wave (set-down) to be included in the group. The experiments show that the low frequency wave is generated during breaking and propagation to the shoreline of the wave group. This process of generation and propagation of low frequency waves is simulated numerically by solving the short-wave averaged mass and momentum conservation equations. The computed and measured results are in good agreement. The mechanism of generation of low frequency waves in the surf zone is examined and discussed.展开更多
The swashing motion on mild beach slope is dominated by the motion of low frequency waves (LFWs). Companying such a motion, there are two types of swashing motion states, occurrence or no occurrence of LFW’s collisio...The swashing motion on mild beach slope is dominated by the motion of low frequency waves (LFWs). Companying such a motion, there are two types of swashing motion states, occurrence or no occurrence of LFW’s collision. The present study distinguishes the two states qualitatively by relating it to the number of generated LFWs for the case of two incident wave groups. A simplified swashing index is established theoretically for this purpose. A series of related experiments were performed to observe the generated out-going LFWs on different mild slope from 1:20 to 1:160 and to determine the critical value of the swashing index. Numerical simulations based on higher order Boussinesq equations are also performed to help the recognition of the LFWs generated in the experiment.展开更多
文摘A nonlinear short-wave-averaged (surf beat) model is presented. The model is based on that of Roelvink (1993), but the numerical techniques used in the solution are based on the so-called weighted-averaged flux (WAF) method (eg Watson et al., 1992), with time-operator splitting used for the treatment of some of the source terms. This method allows a small number of computational points to be used, and is particularly efficient in modelling breaking long waves. The short-wave (or primary-wave) energy equation is solved using a more traditional Lax-Wendroff technique. Results of validation indicate that the model performs satisfactorily in most respects.
基金Supported by Program for New Century Excellent Talents in University of China (Grant No.NCET-04-0267)Program for Changjiang Scholars and Innovative Research Teams of Colleges and Universities of China (Grant No.IRT0420)the National Natural Science Foundation of China (Grant No.50679010)
文摘As an important hydrodynamic phenomenon in the nearshore zone, the cross-shore surf beat is numerically studied in this paper with a fully nonlinear Boussinesq-type model, which resolves the primary wave motion as well as the long waves. Compared with the classical Boussinesq equations, the equations adopted here allow for improved linear dispersion characteristics. Wave breaking and run-up in the swash zone are included in the numerical model. Mutual interactions between short waves and long waves are inherent in the model. The numerical study of long waves is based on bichromatic wave groups with a wide range of mean frequencies, group frequencies and modulation rates. The cross-shore variation in the amplitudes of short waves and long waves is investigated. The model results are compared with laboratory experiments from the literature and good agreement is found.
基金This project was financially supported by the National Natural Science Foundations of China(Grant No.5967900559839330)
文摘The generation of low frequency waves by a single or double wave groups incident upon two Plane beaches with the slope of 1/40 and 1/100 is investigated experimentally and numerically. A new type of wave maker signal is used to generate the groups, allowing the bound long wave (set-down) to be included in the group. The experiments show that the low frequency wave is generated during breaking and propagation to the shoreline of the wave group. This process of generation and propagation of low frequency waves is simulated numerically by solving the short-wave averaged mass and momentum conservation equations. The computed and measured results are in good agreement. The mechanism of generation of low frequency waves in the surf zone is examined and discussed.
基金financially supported by the National Natural Science Foundation of China(Grant No.51879033)
文摘The swashing motion on mild beach slope is dominated by the motion of low frequency waves (LFWs). Companying such a motion, there are two types of swashing motion states, occurrence or no occurrence of LFW’s collision. The present study distinguishes the two states qualitatively by relating it to the number of generated LFWs for the case of two incident wave groups. A simplified swashing index is established theoretically for this purpose. A series of related experiments were performed to observe the generated out-going LFWs on different mild slope from 1:20 to 1:160 and to determine the critical value of the swashing index. Numerical simulations based on higher order Boussinesq equations are also performed to help the recognition of the LFWs generated in the experiment.
