Dam-break induced flows in complex topographies

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Dam-break induced flows in complex topographies Powered By Docstoc
					      Flood propagation
Simulation of the IMPACT case study
    on the Tous dam-break flow



    Université catholique de Louvain

     Sandra Soares Frazão and Yves Zech
                 Overview
• Interpreting of real data into comp. data
  – Representation of buildings
  – Upstream boundary condition
  – Downstream boundary condition
• Runs performed at UCL
• Analysis of the results
  – Water level
  – Discharge
  – Inundated area
• Conclusions
                 Tous test case - UCL computations   2
The Jùcar river and Sumacárcel


                          Tous dam



  Sumacárcel




               Tous test case - UCL computations   3
               Sumacárcel

• Located on a hill near the Júcar



             Sumacárcel




                  Tous test case - UCL computations   4
                Outflow hydrograph
            Q (m³/s)
25000
                                                                     normal
                                                                     lower
20000                                                                mid
                                                                     upper

15000



10000



5000



   0
        0              10         20            30              40             50
                            Tous test case - UCL computations        Time (hour)    5
           Preliminary run

• Localisation of inundated area in town
                                First run with coarse mesh


                     Buildings reached by the flood
                     -> included in the mesh



                    Buildings not reached by the flood
                    -> not included in the mesh



               Tous test case - UCL computations       6
              Meshing of the town
Coarse mesh without buildings         Refined mesh with buildings




                       Tous test case - UCL computations            7
  Upstream boundary condition

Location in the computational data

   1982 bathymetry                       1998 bathymetry




 Dam          Inflow section
                                     Dam

                                                    Inflow section
                Tous test case - UCL computations            8
 Downstream boundary condition

• 1998 bathymetry : OK
• 1982 bathymery : deep hole added to mesh




              Tous test case - UCL computations   9
              Runs performed

• ~4 days / run on Pentium IV processor
• CFL max 0.9

    Run       Bath.     Hydr.         mesh           Resolution
Run 5         1998     normal         55553          20 m / 6 m
Run 7         1982     normal         60911          20 m / 6 m
Run 7 lower   1982      lower         60911          20 m / 6 m
Run 7 mid     1982       mid          60911          20 m / 6 m
Run 7 upper   1982     upper          60911          20 m / 6 m


                 Tous test case - UCL computations            10
       Analysis of the results

• Water level
• Discharge
• Inundated area




              Tous test case - UCL computations   11
             Water level

• Qualitative comparison at gauge n°10
                                                  1982
                               Gauge n°10



                                                  1998




              Tous test case - UCL computations          12
              Water level

• Gauge n°1
                       h (m)
              20
                                                            1982
              16                                            1998

              12

               8

               4

               0
                   0           10     20           30   40        50
                                                         Time (hour)


               Tous test case - UCL computations                 13
              Water level

• Gauge n°4
                       h (m)
              10
                                                             1982
              8                                              1998


              6

              4

              2

              0
                   0           10    20            30   40        50
                                                         Time (hour)


               Tous test case - UCL computations                 14
               Water level

• Gauge n°16
                        h (m)
               10
                                                              1982
                8                                             1998

                6

                4

                2

                0
                    0           10     20           30   40        50
                                                          Time (hour)


                Tous test case - UCL computations                 15
Difference between bathymetry




          Tous test case - UCL computations   16
Difference between bathymetry


           Deeper river bed in
           1998 bathymetry




          Tous test case - UCL computations   17
            Discharge

              Q (m³/s)
25000
                                          15000


20000                                     14000

                                          13000
                                                  19   21          23          25
15000



10000
                                                            Tous outflow
                                                            S1
5000                                                        S2
                                                            S3


   0
        0                10       20            30          40                 50
                                                                 Time (hour)

            Tous test case - UCL computations                           18
             Discharge

            Q (m³/s)
25000                                       25000

                                            21000
20000                                       17000

                                            13000
15000                                               15   17          19          21



10000
                                                              Tous outflow
                                                              S1
                                                              S2
5000                                                          S3
                                                              normal

   0
        0              10          20             30          40                 50
                                                                   Time (hour)

              Tous test case - UCL computations                           19
            Inundated area

• In the town




                Tous test case - UCL computations   20
                                        Inundated area

        7000
                                 4400


        6500                     4200


                                 4000
        6000
                         y (m)


                                 3800


        5500                     3600


                                 3400
y (m)




        5000
                                 3200

        4500
                                        2200   2400   2600    2800   3000
                                                      x (m)
        4000

        3500
                                                                            normal
                                                                            mid
        3000
                                                                            upper
               1000      2000                   3000
                      x (m)

                                                      Tous test case - UCL computations   21
                  Inundated area

• Smaller extent for upper hydrograph
  than for normal: V2 > V1
             Q (m³/s)
     25000
                                                          Q normal
     20000                                                Q upper
                         V1
     15000
                                            V2

     10000

      5000

        0
             0          10          20         30        40          50
                                                          Time (hour)
                             Tous test case - UCL computations            22
              Conclusions

• Main difficulties
  – Handle the huge size of data
  – Mixed scales
  – Boundary conditions
  – Steep slopes: topographical source terms
• Encouraging results



                Tous test case - UCL computations   23
Thank you for your attention!




    Sandra Soares Frazão and Yves Zech

				
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