dsd-nl 2014 - nghs flexible mesh - technital pilot modeling venice lagoon, katherine cronin,...
TRANSCRIPT
Friday, June 20, 2014
NEXT GENERATION MODELLING APPLIED TO THE VENICE LAGOON
G.T. Menel Lemos, E. Jeradi
Next Generation Hydro Software Symposium – 2014
Friday, June 20, 2014
NEXT GENERATION MODELLING APPLIED TO THE VENICE LAGOON
2nd Batch Pilot case
New Venice lagoon D-Flow-FM model:
• Set-up of the grid
• Test runs
• Verification of the results both with the measurements and 3D-Flow model
• Evaluate the performance
DELWAQ:
• Coupling of the FM version of the Venice lagoon model (converted during the 1st phase pilot study)
• Test runs with simple water quality process • Comparison of results with the 3D-Flow Venice lagoon
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon
VENICE LAGOON: SENSIBLE ENVIRONMENT
Venice Town
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon
EXISTING 3DFLOW VENICE MODEL
Existing 3DFlow Venice Model version:
• Need to use Domain Decomposition even in the “single domain” version: internal boundaries used to avoid too much cells in the seaside
• Useless cell concentration in deep areas potentially create problems – see area in front of the inlets
• Low resolution in marginal areas (northern and southern part of the lagoon) don’t allow a good representation of morphological structures
• Need many different schematizations : each different intervention have its own model…
Good representation (small cells) → small time step → long time run
Friday, June 20, 2014
NEXT GENERATION MODELLING APPLIED TO THE VENICE LAGOON
1st batch pilot case :
• Conversion of the old model • Run of the FM version of the old model
• Comparison of results both with the measurements and 3D-Flow model
• Evaluate performance
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 1ST BATCH PILOT CASE
D-FLOW VERSION
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 1ST BATCH PILOT CASE
3DFLOW VERSUS D-FLOW: WATER LEVELS
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 1ST BATCH PILOT CASE
3DFLOW VERSUS D-FLOW: FLUXES
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 1ST BATCH PILOT CASE
PERFORMANCE
CPUtime steps / Nr of TimeSteps
TtimeStep FM/ TtimeStep 3DFlow
Run time FM/Run time 3DFlow
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 1ST BATCH PILOT CASE
PERFORMANCE: CPU usage
D-Flow Flexible Mesh was run in OpenMP mode.
Delft3D-FLOW D-Flow Flexible Mesh
Delft3D-FLOW does not have the possibility to use OpenMP.
100% usage of the four cores for D-Flow Flexible Mesh does not mean that the simulation went a factor of four faster because the algorithm is for a large part sequential but this explains why D-Flow Flexible Mesh was about a factor of two faster.
Friday, June 20, 2014
NEXT GENERATION MODELLING APPLIED TO THE VENICE LAGOON
2nd Batch Pilot Case
New Venice lagoon D-Flow-FM model:
• Set-up of the mesh
• Test runs
• Verification of the results both with the measurements and 3D-Flow model
• Evaluate the performance
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon – 2nd BATCH PILOT CASE
1. Define curvilinear grid for all the main channels
D-FLOW VENICE MODEL: MESH CREATION
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
1. Define curvilinear grid for all the main channels 2. and inlets and sea (with different resolutions)
D-FLOW VENICE MODEL: MESH CREATION
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
1. Define curvilinear grid for all the main channels 2. and sea area (with different resolutions) 3. Define grid of marshlands (based on samples)
D-FLOW VENICE MODEL: MESH CREATION
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
D-FLOW VENICE MODEL: COMPLETE MESH
1. Define curvilinear grid for all the main channels 2. and sea area (with different resolutions) 3. Define net of marshlands (based on samples) 4. Define net in the shoals area
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
~ 170.000 nodes 400.000 links
D-FLOW VENICE MODEL: COMPLETE MESH
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
D-FLOW VENICE MODEL: NORTHERN PART
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
NEW D-FLOW VENICE MODEL: BATHYMETRY
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
NEW D-FLOW VENICE MODEL: BATHYMETRY
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
1. Define curvilinear grid for all the main channels
2. and sea area (with different resolutions)
3. Define grid of marshlands (based on samples)
4. Define grid of the flat areas
NEW D-FLOW VENICE MODEL: ORTHOGONALITY
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
NEW D-FLOW VENICE MODEL: RESULTS
Water level
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
Node velocity
NEW D-FLOW VENICE MODEL: RESULTS
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
Velocity field – northern lagoon
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
Velocity field – central lagoon
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
Velocity field – southern lagoon
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
COMPARISON BETWEEN MODELS AND MEASUREMENTS
Fluxes Water levels
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
PERFORMANCE
CPUtime steps / Nr of TimeSteps
TtimeStep FM/ TtimeStep 3DFlow
Run time FM/Run time 3DFlow
3DFlow - 5 domains DFlow-FM-new
Timestep (s) 3 auto (CFL)
Simulation period (s) 604800 604800
Nr of timesteps ( ) 201600 223262
CPUtime steps (s) 125815.88** 88787.97
Run time (hh:mm:ss) 22:46:14 18:01:20
TtimeStep 0.624087 0.397685
SpeedFactor TimeStep 0.637227
SpeedFactor Wall Clock 0.791470
**Average cpu time of the 5 domains (not considering ddmodule wait time)
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
OPTIMIZATION OF THE NEW MESH
remove unnecessary links to save computational time (wagon wheels)
De-refine the mesh in the marshlands and shoals
Friday, June 20, 2014
NEXT GENERATION MODELLING APPLIED TO THE VENICE LAGOON
2nd Batch Pilot case
DELWAQ:
• Coupling of the FM version of the Venice model (curvilinear grid)
• Test runs with simple water quality process • Comparison of results with the 3D-Flow Venice lagoon
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
DELWAQ
Coupling procedure
Using offline coupling (communication file) and ddbound option to account for dd internal boundaries Pros: • hydro run can have different duration and save only
last cycle • to communication file • It is possible to aggregate the grid before coupling it
Cons: • Communication file can be enormous • Coupling with ddmodel can be tricky (need manual
modifications of the *.hyd files)
Using online coupling by activating WaqInterval option in the mdu file Pros: • No communication file: creation of WAQ files
(.are, .vol, .flo, etc.) directly • Simple procedure
Cons: • hydro run must have the same duration of
the cycle for WAQ • It is not possible to aggregate the net ** (**for the moment but it will be possible to create the WAQ files on an aggregated grid)
3D-FLOW ddmodel D-FLOW
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
DELWAQ: TEST RUN
Hydrodynamic conditions: • Average tide : semidiurnal +- 35 cm • No wind • Average river flows
WAQ conditions: processes initial sea/river bnd
• Continuity (g/m3) 1 1/1 • Salinity (g/kg) 33 33/0 • Cons. tracer (g/m3) 1 1/0
• Duration: 20 days, time-step 5 min • Dispersion: 5 m2/s • Numerical scheme: 15 Iterative solver, backward diff.
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
DELWAQ: TEST RUN RESULTS - CONTINUITY
3D-FLOW D-FLOW
After the coupling procedure for the 3D-Flow model a utility called “flocheck” has been used. This utility makes a kind of “dredging” to increase the volume and/or lateral surface of isolate segments in order to keep the residence time below the user-defined integration time-step.
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
DELWAQ: TEST RUN RESULTS - SALINITY
3D-FLOW D-FLOW
Rivers are defined in different way in the two hydro models and so different in the WAQ: • 3D-Flow - as discharges • D-Flow - discharges boundaries Same dispersion coefficient: 5 m2/s
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon - 2nd BATCH PILOT CASE
DELWAQ: TEST RUN RESULTS – CONSERVATIVE TRACER
3D-FLOW D-FLOW
Rivers are defined in different way in the two hydro models and so different in the WAQ: • 3D-Flow - as discharges • D-Flow - discharges boundaries Same dispersion coefficient: 5 m2/s
3D-Flow seems to have more long time response than the D-FLOW model
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon
FURTHER DEVELOPMENTS
D-FLOW:
1. Complete the optimization the new grid: marshland and shoal areas
2. 3D simulations
DELWAQ:
1. Go further with the analysis of water quality parameters
2. Make comparisons with measurements
Friday, June 20, 2014
Next Generation Modelling applied to the Venice Lagoon
COMMENTS
D-FLOW:
• There was no easy way to de-refine the triangular mesh. The existing method
involves making a polygon and merge nodes and than smooth/orthogonalize
again. The procedure is very time consuming in such complex system
• It will be nice to have some kind of filter (like neighborhood) function to cleaning up
the samples before using it for the net generation
DELWAQ:
• The new WAQgui save the *.inp file with an error in the 7# block: the line that
starts with MASS/m2 have to be deleted otherwise WAQ1 gives an error and
doesn’t work
• It is not possible to defined an spatial varying initial condition using the FM mesh
Quickplot (April version):
• It is not possible to define a manual color scale limit
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