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IMPACT - WP4 Sediment movement Work overview. Université catholique de Louvain Nicolas le Grelle, Benoit Spinewine and Yves Zech. Scope of the research. Near-field Severe transient debris flow Far-field Bank erosion and geomorphic changes. Near field : problems to be solved. Propagation
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IMPACT - WP4Sediment movementWork overview Université catholique de Louvain Nicolas le Grelle, Benoit Spinewine and Yves Zech Sediment movement - UCL
Scope of the research • Near-field • Severe transient debris flow • Far-field • Bank erosion and geomorphic changes Sediment movement - UCL
Near field : problems to be solved Propagation • Intense scouring • Debris-flow front Sediment movement - UCL
Dam-break near field • Experiments : uniform material (UCL) • Rising gate • Same bed levels • Sediments swept along the rising gate • Limited water depth Sediment movement - UCL
Dam-break near field • Construction of a new flume • Downwards moving gate • Various bed levels • Possibility of enlargement Sediment movement - UCL
Dam-break near field Sediment movement - UCL
z pure water mixture u Dam-break near field • Mathematical modelling • 1D model : • Velocity distribution • Concentration distribution Sediment movement - UCL
Dam-break near field • Validation of codes • Benchmark BM UCL 1 :1D dam-break flow in the near field h00.10 m hs L = 0.10 m Sediment movement - UCL
Far field : problems to be solved • Geomorphic changes • Bank erosion and failure • Tractive forces applied • Failure mechanism • Channel widening Brooks & Lawrence, 1999 Sediment movement - UCL
Far field : programme • Laboratory experiments • Dam-break in an initially prismatic valley • Large-scale model (Châtelet) • Numerical modelling • Validation (UCL, UDT, Cemagref, IST) • Laboratory tests • Field cases Sediment movement - UCL
Far field : programme • Laboratory experiments • Dam-break in an initially prismatic valley • Large-scale model (Châtelet) • Numerical modelling • Validation (UCL, UDT, Cemagref, IST) • Laboratory tests • Field cases Sediment movement - UCL
Dam-break far-field • Laboratory experiment • Dam-break in an initially prismatic valley Sediment movement - UCL
Dam-break far-field • Laboratory experiment • Dam-break in an initially prismatic valley Sediment movement - UCL
1 3 2 Dam-break far-field Dam-break in an initially prismatic valley Sediment movement - UCL
Dam-break far-field • Dam-break in an initially prismatic valley • Images treatment Sediment movement - UCL
Dam-break far-field • Dam-break in an initially prismatic valley • Reproducibility t = 1 s Sediment movement - UCL
Dam-break far-field • Dam-break in an initially prismatic valley • Reproducibility t = 5 s Sediment movement - UCL
57 cm 16 cm 50° 8 cm 30 cm Upstream Downstream Dam-break far-field • Dam-break in an initially prismatic valley • Initial conditions (benchmark) Sediment movement - UCL
Far field : programme • Laboratory experiments • Dam-break in an initially prismatic valley • Large-scale model (Châtelet) • Numerical modelling • Validation (UCL, UDT, Cemagref, IST) • Laboratory tests • Field cases Sediment movement - UCL
Dam-break far-field • Large scale model at LRH-Châtelet Sediment movement - UCL
3,90 m 1,535 m Dam-break far-field • Large scale model at LRH-Châtelet Weight = 190 kg Jack = 2400 N Opening time = 1 sec Sediment movement - UCL
h0 h s Gate 1 m Dam-break far-field • Large scale model : Test 1 - Calibration Sediment movement - UCL
h0 hs Dam-break far-field • Large scale model : Test 2 - Benchmark Sediment movement - UCL
1 m 3 m Section AA Section BB h0 hs AA BB Dam-break far-field • Large scale model : Test 3 - Benchmark Sediment movement - UCL
Far field : programme • Laboratory experiments • Dam-break in an initially prismatic valley • Large-scale model (Châtelet) • Numerical modelling • Validation (UCL, UDT, Cemagref, IST) • Laboratory tests • Field cases Sediment movement - UCL
Dam-break far field • Sand behaviour for small-scale laboratory exp. • Humid sand • Residual water • Apparent cohesion • Disappears when underwater • « Rotating tank » experiments • Different angles of repose • Emerged • Submerged Sediment movement - UCL
Dam-break far field • Modelling of bank failures • Simple model accounting for discrete mass failure events • Distinct angles of repose for submerged and emerged banks • Failure triggered whenever and wherever critical angles exceeded • To be extended to 2D by invoking conic failure surfaces Sediment movement - UCL
Dam-break far field • 1D Numerical modelling • Hydrodynamic: finite volume, Roe • Sediment transport: non-equilibrium, bed and submerged banks • Bank failure • Two angles of failure (emerged & submerged) • Two angles of repose (emerged & submerged) Sediment movement - UCL
Far field : programme • Laboratory experiments • Dam-break in an initially prismatic valley • Large-scale model (Châtelet) • Numerical modelling • Validation (UCL, UDT, Cemagref, IST) • Laboratory tests • Field cases Sediment movement - UCL
Comparison • 1D Numerical modelling Sediment movement - UCL
Comparison • 1D Numerical modelling Sediment movement - UCL
Comparison • 1D Numerical modelling Sediment movement - UCL
Comparison • 1D Numerical modelling Sediment movement - UCL
Comparison • 1D Numerical modelling Sediment movement - UCL
Comparison • 1D Numerical modelling Sediment movement - UCL
Comparison • 1D Numerical modelling Sediment movement - UCL
Comparison • 1D Numerical modelling Sediment movement - UCL
Comparison • 1D Numerical modelling Sediment movement - UCL
Comparison • 1D Numerical modelling Sediment movement - UCL
Comparison • 1D Numerical modelling Sediment movement - UCL
Far field : programme • Laboratory experiments • Dam-break in an initially prismatic valley • Large-scale model (Châtelet) • Numerical modelling • Validation (UCL, UDT, Cemagref, IST) • Laboratory tests • Field cases Sediment movement - UCL
Dam-break far field • Field test : Lake Ha!Ha! Brooks & Lawrence, 1999 Sediment movement - UCL
IMPACT - WP4Sediment movementWork overview Université catholique de Louvain Nicolas le Grelle, Benoit Spinewine and Yves Zech Sediment movement - UCL