University:
Boston University
Course:
CAS EE 645 | Physical Models in Remote Sensing
Academic year:

2021
Views:

372

Pages:

22
Author:

SpaceCadet101

NONLINEAR PROPAGATION OF STORM WAVES: INFRAGRAVITY WAVE GENERATION AND DYNAMICS PRESENTATION OUTLINE I. Motivation II. Nonlinear Wave Propagation in the Nearshore III. A Numerical and Experimental Study on Infragravity Waves IV. Chile as an International Natural Coastal Laboratory 11. NONLINEAR WAVE PROPAGATION PASI Coastal Hazards 2013 Boston University-Mechanical Engineering UTFSM 2-13 January 2013 Shoaling zone Surf zone swash zone z = η(x,t) Ca C L Nonlinearity & a/h Dispersion = h/L σ= H ho 10 Long wave (shallow water) models σ≤ 0.1 II. NONLINEAR WAVE PROPAGATION Wave merging in the inner surf zone Sénéchal, Dupuis, Bonneton (2001) Higher harmonics release after a bar Sénéchal, Bonneton, Dupuis (2002) II. NONLINEAR WAVE PROPAGATION Regular waves shoaling over a submerged bar, and higher harmonics release once water depth increases → Generation of bound higher harmonics in the shoal (shallow water propagation) Over "intermediate" depths, higher harmonics travel at their "own" speed 10400002m 11.00 0.05 127 #ope-1/05 0.04 Source: Cienfuegos et al., 2007; Dingemans, 1994 experiments. II. NONLINEAR WAVE PROPAGATION Wave propagation creates a set-down and set-up in the mean sea level Fission of the main wave front for longer period waves II. NONLINEAR WAVE PROPAGATION Set-down/Set-up over a uniform beach under regular wave propagation Radiation stress concept for wave-averaged quantities (Longuet-Higgins and Stewart, 1962) graph showing setdown and setup over a uniform beach ∂S_xx/∂x + ρg(η + h) ∂η/∂x = 0 S_xx = E[cos²θ + 1/2] II. NONLINEAR WAVE PROPAGATION Infragravity wave (IG) generation under random wave forcing Long waves forced by high-frequency wave groups 2nd Order Long Wave Generation Mechanism Negative correlation between group envelope and IG waves graph showing characteristics of a group of waves Mean water level pulsation associated to wave groups' set-up/set-down (Longuet-Higgins and Stewart, 1962) Bound long waves propagating at group velocity