INUNDATION MODEL FOR HIGHLY URBANIZED AREA

The flood inundation model for highly urbanized area is different from general flood models due to the increase of the complexity of nature and the internal boundaries. As consequences, the flow is more complex and requires a stable numerical model. Here is a flood inundation model for highly urbanized area (SUIKOU-2D) that meets all those challenges.

Suikou has meaning the flow of water in Japanese. Sui is mizu or water and Kou is Iku or go. Although Japanese don't use this word "Suikou" instead of "Kyuuryuu" or "gekiryuu", this word was especially adopted as a name of this numerical code. SUIKOU-2D was written in FORTRAN-77 for Finite Difference Method, MACCORMACK SCHEME combined with ARTIFICIAL VISCOSITY SCHEME. These schemes allow to smoothly perform a numerical simulation of two-dimensional depth-averaged flow.

This model was tested to simulate and to evaluate the past flood inundation in 2004, Aioi area in Kofu, Yamanashi. It was a heavy storm with 78mm/hr of intensity resulted overflows from drainage channels and yielded a severe inundation in Aioi area.
Compared to the observed data, the numerical result was good. Then, it is supposed to be a useful tool for the water authority and the local government to design the countermeasures, to assess the inundation processes and to provide the potential inundation hazard map.

Result of 1 hour flooding (flood.avi).

An example of inundation process is as follow:


Link:
Sisinggih D., S. Oishi and K. Sunada: Flood Inundation Model for Highly Urbanized Area and Its Application to Simulate the Flood Inundation in 2004, Kofu-City, Japan, Annual Journal of Hydroscinece and Hydraulic Engineering, Vol.52, 2008.2

Partial dambreak

To run a simple test of two-dimensional problem with SUIKOU-2D.FOR, there are seven input files required. Say, an example of simple dambreak problem. The computational domain is 200m x 200m and 5m x 5m mesh. The initial water level is maintained as 10m at the upstream dam and tailwater was 5m.

The input files to run the codes are:
geo.txt --> contains the geometry information on each node.
mesh.txt --> describe the mesh size and its numbers (dx,dy, nx,ny)
ctrl.txt --> setting up parameters, and hydraulic constants.
elv.txt --> contains the information of bed elevation data.
ho.txt --> initial water depth.
uo.txt --> initial velocity in x-direction.
vo.txt --> initial velocity in y-direction.

Screenshot of Running program :

The output file is ready formatted for GNUPLOT visualization.

• Assumed it is in the directory of output files, then simply run the GNUPlot.
• Type a command shown in the figure below (for advanced plotting, please refer GNUPLOT manual).

and it gave :



If it's need, the animations could be made.

The Water Surface animation

The vector velocity animation

(Reference: Open Channel-Flow, Chaudhry M.H, 1993. pp. 371-374)

Flow around rectangular block

The water surface animation


The vector velocity

Aioi's flood in 2004

This animation was created with SUIKO-2D. (approximately 5MB).