Calibration (under increasing complexity)

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Against the background of the 2km x 30Ha Levisham hydraulic analysis – here –  the table below lists 2D models run to assess the productivity of finite element meshes derived from assembled point clouds of increasing complexity.  Denser point clouds are tested towards a productivity goal of 30,000 CFD nodes solved in real time x 3  (ie:  a 15 minute time-series fed to a 500ha x 20node/ha floodplain & solved to 1% convergence in 5 minutes) .

References:  OS map here,  relief map here, and animation here

Model km x Ha In-Flow Tributaries Out-Flow Graphics
pk2a1 12 x 160 3 @ 67.0 none Q=0.07H^1.8 Here
pk2a4          
pk2b6          
pk2b7          

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Column Heading Legend

  • Model filename: ‘pk’=pickering; ‘2’=12km reach; ‘a,b’=configuration; ‘1’=build
  • Footprint: River length (km) and ‘Q-T200’ wet area (ha)
  • In-flow discharge characteristics: m3/s x water surface level aod
  • Tributary discharge inflow (m3/s)
  • Out-flow discharge relationship : H=stage; k & m parameters of flume equation Q = kH^m
  • Graphic: Click for illustrations relating to hydraulic models

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Models

a. Steady Flow; Main channel only; Vee discharge in; Flume discharge out

pk2a1  4000 node point cloud budget;  elevation data resampled from various sources; Productivity goal = 24hr hydrograph in 50mins @ 3% convergence tolerance; vee-form bed; build 1 canalises the flow to test boundary flumes;  tributaries and friction features excluded; TIN points from ‘risk’ buffer  GIS lines below;

  1. River centreline resampled @ 16m to 760 nodes; elevation from smoothed radar minus 3m
  2. Tributary centrelines resampled @ 16m; elevation also from smoothed radar minus 3m
  3. Flumes :  Inflow (North, Levisham) and outflow (South, Ropery Br) built relative to first & last c/line points and outwith the boundary of terrain elements
  4. LR (LeftRight) banklines; buffer=4m; excluded from this CFD mesh
  5. LR bermlines; buffer=8m; resampled @ 16m to 1520 nodes; elev=radar+3
  6. LR Q24lines; buffer=24m; resampled @ 32m to 760 nodes; elev=radar+3
  7. LR Q40lines; buffer=40m; resampled @ 64m to 276 nodes; elev=radar+3
  8. LR Q100lines; buffer=50m; resampled @ 50m to 380 nodes; elev=radar
File structure for River 2D terrain TIN and CFD Mesh  
For TIN (.bed) file in R2D

  • assemble in 5 cols excel; counter-clockwise bdy pts first,  delimited by [pts }; flumes and perimeter points last; Triangulate; add breaklines (brackets or GUI);  rename and adjust flume pts on boundary
  • save as .bed file from R2D_bed app; open in notepad++ and delete list defining bdy pts as breakline pts; check for extra points and rename; make high and low friction versions
  • nb: nodes. then breaklines. then boundary.
  • perimeter points (which surround bdy pts) always after last node

For CFD (.msh) file in R2D

  • copy .bed point assy
  • move bdy cols one row to the right and insert x col
  • move bdy rows UP and insert below last node (ie above “no more breaklines.”
  • remove perimeter points

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Location Map

Pickering Beck
Pickering Beck

 

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