Group Research Teaching Activity

Domain decomposition method for coastal ocean flow

 


1. Coupling of SWM/FVCOM


A shallow water model (SWM), which is based on the shallow water equations and a Godunov scheme, is coupled in two-way with FVCOM, a finite volume coastal ocean model. In the hybrid modeling system, FVCOM is used to capture large scheme background flows, the SWM is employed to resolve local phenomena such as flooding and surge bore.


 

(a) Meshes

(b) SWM

 

(c) FVCOM

 

(d) SWM-FVCOM

 

Figure 1. Modeling of a dam break flow.

 

 

 

 

Figure 2. Comparison of solutions for the dam-break flow along a line in the x direction and past the opening.

 


2. Coupling of CFD/FVCOM


A fully 3D, unsteady, incompressible flow CFD model has been coupled with FVCOM. The CFD model uses curvilinear coordinates and overset grids, and FVCOM utilizes triangle meshes and sigma coordinates. The coupling is two-way and realized the Schwarz alternative iteration. The coupling systems targets modeling of multi-scale/multi-physics coastal ocean flows that are beyond the reach of traditional coastal ocean models. The following are a few examples modeling results obtained with this approach.


1) Flow over sill

 

In the modeling of a flow over a sill, as shown as follows, it is seen that on Fig. (d) and (e), that the solution of the CFD/FVCOM coupling has the features of that obtained by the CFD apporach.


 

(a) Horizontal mesh

(b) Vertical mesh

(c) FVCOM only

(d) CFD only

(e) CFD/FVCOM coupling

 

Figure 3. Meshes and solutions by FVCOM, CFD, and the CFD/FVCOM coupling. The red and blue mesh are grid of CFD and FVCOM, respectively.


2) Thermal effluent at seabed


 

(a) Diffuser

(b) Mesh for diffuser

 

(c) Meshes of CFD and FVCOM

 

(d) FVCOM mesh

(e) Solution at a horizontal plane above the diffuser




(f) 3D view of the thermal plumes


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(g) Animation of 3D thermal plume

 

Figure 4. Meshes and solutions for the thermal discharge at bottom of ocean.

3) Flow past coastal bridge


 

(a) Meshes for CFD and FVCOM










(b) CFD mesh

(c) Solution of background flow 








(d) Flow at a horizontal plane








(e) 3D view of velocity iso-surface

 

Figure 5. Meshes and solutions for the flow past a coastal bridge.