Speaker 1 :  Takeshi Kataoka  (Kobe University)
    Date & Time : August 20th (Fri.), 2021 / 10:00-10:40PM (Tokyo (JST)) 
    Title : Strong nonlinear effects in steady radiating free-surface waves
    Abstract : 
         The generation of steady gravity surface waves due to flow past a localized
       bottom topography or applied pressure is studied based on potential flow 
       theory. The linear solution to this classical problem is readily found by 
       Fourier transforms, and the nonlinear response has been studied extensively 
       by numerical methods. When the topography is a bump (positive applied pressure), 
       the nonlinear response of downstream wave is significantly greater than that 
       of the linear theory. On the other hand, when the topography is a hole 
       (negative applied pressure), the wave response is far smaller than that of 
       the linear theory. We observe that the longer the topography, the stronger 
       the effects of nonlinearity. It is concluded that the linear theory has very 
       limited range of validity. This is a joint work with T. R. Akylas.