Absorbing–generating seaward boundary conditions for fully-coupled hydro-morphodynamical solvers

Abstract

Nicholas (2015) Absorbing-generating seaward boundary conditions for fully-coupled hydromorphodynamical solvers. Coastal Engineering, 99 . pp. 96-108. ISSN 0378-3839Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/44700/1/09_paper%20Briganti.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the Creative Commons Attribution Non-commercial No Derivatives licence and may be reused according to the conditions of the licence. For more details see: http://creativecommons.org/licenses/by-nc-nd/2.5/ A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk Firstly, the generation and absorption of single monochromatic waves are studied to quantify the error after the reflected wave exited the domain. In all cases the error is always small, giving evidence of the effectiveness of the new seaward boundary conditions. Furthermore, the propagation and reflection of a monochromatic wave train over a mobile bed are considered. Both flow evolution and bed change are not affected by spurious oscillations when long sequences of waves are tested. Additionally, a very low mobility bed is considered to simulate a 'virtually fixed' bed and new boundary condition results consistently converge to those for the hydrodynamic only case. Finally, the reflection of a uniform bore over a mobile bed is studied. For this case the Rankine-Hugoniot conditions provide an analytical solution. It is apparent that the adopted linear approximations produce errors in the velocity estimates. Nevertheless, the conditions perform reasonably well even in this demanding non-linear case.

Swash zone morphodynamic modelling including sediment entrained by bore-generated turbulence

“…This approach is better suited to illustrate the shock development and sediment entrainment process, although we note that the resulting event will be different A solitary wave is driven from the seaward boundary (x = 0), which is assumed to be absorbing / generating, such that dependent variables at the seaward boundary are approximated following the technique in [19].…”

Numerical study of periodic long wave run-up on a rigid vegetation sloping beach

“…(1) and (2) are reduced to the linear long-wave equations and expressed in characteristic form to prescribe the incoming wave while allowing reflected waves to exit the computational domain. The detailed procedures of characteristic methods for a periodic waveincident boundary condition can be found in the referencesKobayashi et al (1987) andIncelli et al (2015).…”

Bottom changes in coastal areas with complex shorelines

“…Extant studies (Drønen & Deigaard, 2007;Kim & An, 2011) have simulated the bed evolution dynamics using a quasi-three-dimensional approach (Q3D) in which the advective terms are related to the vertical profile of the horizontal velocity and the vertical profile of the suspended sediment concentration. Other authors (Burger, Kumar, & Ruiz-Baier, 2015;Incelli, Briganti, & Dodd, 2015;Khosronejad, Kang, Borazjani, & Sotiropoulos, 2011;Li & Duffy, 2011) have calculated the morphological changes by means of fully coupled models, which simultaneously solve the nonlinear shallow water and Exner equations. Such full coupling allows one to easily implement different closure laws or to solve an advection equation to represent the suspended sediment transport.…”