, 5, 62 NUMERICAL SIMULATIONS OF URBAN FLOODING DUE TO DIKE BREACHING 1 2 Juichiro AKIYAMA and Mirei SHIGE-EDA 1 Ph.D. 84-855 1-1 2 () The flooding process of the Misumi district due to dike breaking of the Misumi River, occurred in July 1983, is simulated by a two-dimensional numerical model for urban flooding. The model employs the finite volume method on unstructured grid using flux-difference splitting (FDS) technique. Such characteristics of the flood plain as submerged/emerged topography, density and arrangement of buildings and houses, streets, flood retarding plantation as well as the characteristics of the river are considered in the simulations. It is shown that the model is capable of reproducing the complex inundation process in an urban area and hydrodynamic forces on buildings and houses with reasonable accuracy. Key Words : urban flooding, dike breaking, numerical simulation, unstructured grid system, finite-volume method,flux difference splitting 1. 9 4 1),2) 3) 4) 5) 6) 2 3) 5) 4) FDS 2 SA-FUF-2DF(Spatial Averaged Finite-volume method on Unstructured grid using Flux-difference splitting technique for 2D Flood flows) 7) 8) 9) 1)
1 t=495minutes 2.8m 25m t=495minutes t=5minutes t=55minutes 25m D A E B F 1.4m 2.8m / 6) 3 7 11) 12) 13) 14), 7),8) 12) 13) 14) FDS 2) 1983 7 2. Discharge (m 3 /s) 3 25 15 1 5 C 18 36 54 72 9 18 t (minutes) 1 7),15),8),9),1),11),16) 3. 1983 7 7 23 7 23 8 8 3 2) 1 2) n=.4
t=35 (minutes) 3 6 t=425 (minutes) 5 1 t=495 (minutes) 5 1 t=35 (minutes) t=425 (minutes) t=495 (minutes) 3 6 3 6 3 6 2 ())(t=35 t=425 t=495 ) n=.43n=.67 a C d.8 1.2 x y F x = C d a/2 uh u 2 + v 2 F y = C d a/2 vh u 2 + v 2 17) 1 t = hx u y v h v =.1m u = v = 11) 1 ( 1) (Case1) (Case2) (Case3) 3 Case2 2) 1 8:15AM t=495 1 Case2 1 Case3 2 (t=35 ) (t=425 7:AM (t=495 8:15AM (Case1Case3 ) 1 (1)
Case1 5 1 Case2 5 1 Case3 5 1 Case1 Case2 Case3 3 6 3 6 3 6 3 ( 5 (t=5 )Case1Case2Case3) t=35 5:3AM, (2)t=425 7:AM t=495 t=495 2.4m 5m 2) 3m 5m 3 5 Case1Case3 (1) Case1 Case2 Case3 Case3 (2) (3) 4 DF (1) D (2) E (3) F E
4 5 A 6 B C 5 A ( 1) (1)Case2 Case3 A (2) Case3Case2 Case1 Case2 Case3 1 Case3 6 Case2 Case3 7 (U 2 h) U = (u 2 + v 2 ) 1/2 2) (1) (2) (3) (4) 7 (5) 3 35 4. 1983
7 (Case1Case2 Case3 7 (1) (2) (3) (3) B1736237 1),, 57,, 26 B-2, pp. 19 126, 1983. 2), - -,, Vol. 27 B-2, pp. 1 18, 1984. 3),,, No. 593/II-44, pp. 41 5, 1998. 4),,,,, No. 6/II-44, pp. 23 36, 1998. 5),,,,, No. 698/II-58, pp. 1 1, 2. 6),,, 48, pp. 577 582, 4. 7),, 1 2 2,, No. 75/II-59, pp. 31 43, 2. 8),,,,, 46, pp. 833 838, 2. 9),,, No. 74/II-64, pp. 19 3, 3. 1),,, 47, pp. 871 876, 3. 11), 3 7,, 49, pp. 619 624, 5. 12),,, 29 B-2, pp. 431 45, 1986. 13),,,,, 11, pp. 121 126, 5. 14),, 4 7,, 49, pp. 577 582, 5. 15),,, 2,, 45, pp. 895 9, 1. 16),,, 2,, 48, pp. 631 636, 4. 17),,,,, 58 7, 1984. (5. 9. 3 )