Updated ... SUIKOU-2D Ver. 1.1 (April 2008)

What's new with the updated version??

1. diffusion-dispersion terms, turbulent and dispersion stresses are added in the new version of SUIKOU-2D. The dispersion terms are produced because of the non-uniformities of the fluid flow velocity in the vertical direction during the depth-averaging. The determination of these terms requires knowledge of the information in the secondary flows across the depth which is, however, usually not known a priori. These terms are frequently found to be negligible in cases such as straight channel flows. However, the dispersion terms can be very important, particularly when there are strong secondary flows, such as fluid flows through a complex domain. The diffusion terms are supposed to overcome the elevation depressions or obstacles.

2. a wetting-drying algorithms.

3. integrating TVD (total variation diminishing) and Artificial Viscosity schemes to get better numerical dissipation control. It has been proved to increase the model robustness.

4. better formulation for numerical treatment of Bed Slope Source Terms

The worked example (click image for animation):
1. Dambreak with rectangular barrier
(Currently there is problem on blogger.com to support animation)

2. Multiple blocks

Sediment Transport in Reservoir

Environmental concerns in lakes and reservoirs due to anthropogenic changes has prompted a need for mathematical modeling tools that can be used as a decision support system for watershed management issues. In order to get a better understanding of flow circulations, the interactions between flow and bottom and the sediment distribution, the hydrodynamic modeling is absolutely required. Here is a summary of an example numerical simulation of reservoir hydrodynamics, the sediment-transport process and its distribution.

The upper Brantas River
The 2002 and 2003 survey provided 17 cross-sections along the upper part of Brantas River and 32 cross-sections along Lesti River. The reaches are 3,645 m 7,746 m from dam axis for Brantas River and Lesti river respectively.


Sediment Transport
By employing GIS-techniques, changes of reservoir volume and bathymetry are determined. The portion of results is given in the below figures.



Compared to the observed data, they seem to be good enough.
Year 2002, the difference = 4.925.454,618 m3 – 4.527.583.411 m3 (observed)
= 397.871,207m3 ~ 8.8% of error
and
year 2003, the difference = 3.698.383,96 m3 – 3,663,658 m3 (observed)
= 34.725,64 m3 ~ 0,95% of error.



NUMERICAL MODELING
1. Grid generation - DEM ( derived from 1:25.000 map)

2. Hydrology Data



Example run #1.
Assuming the reservoir is almost empty in this stage, only 0.1m in depth of water playing as initial condition. The spillway on Dam maintains the water depth of the reservoir at 0.65m. The boundaries are set as a constant water depth in Brantas River at 0.10m and a flood in Lesti River. The flood is rising up to 1.65 m within 1200s and slowly decreasing to 0.25 at 7200s. Total computational time is 10800s.

(click here for an animation with 360s in interval).

be continued with sediment transport modules ...

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).