www.baw.de
Mesoscale horizontal flow-field modelling at
a channel-river-junction
Frank Platzek, Regina Patzwahl, Herman Kernkamp, Sander van der Pijl,
Jacek Jankowski, Boris Glander, Leo Stadler, Bernd Hentschel, Jan Becker
www.baw.de
More
Mesoscale horizontal flow-field modelling at
a channel-river-junction
Bereich für das Einfügen von Bildern über den Menüpunkt Einfügen: Grafik
Dieses Textfeld bitte löschen! Frank Platzek, Regina Patzwahl, Herman Kernkamp, Sander van der Pijl,
Jacek Jankowski, Boris Glander, Leo Stadler, Bernd Hentschel, Jan Becker
Mesoscale horizontal flow-field modelling at a channel-river-junction
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
OUTLINE
• Geometrical setting
• Field measurements
• Scale model
• Numerical model
• grid,
• boundary conditions,
• numerical settings,
• results
• Conclusions
Mesoscale horizontal flow-field modelling at a channel-river-junction
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
• Geometrical setting
• Field measurements
• Scale model
• Numerical model
• Conclusions 2013
• Channel mouth re-design
• Results
• Sheet pile wall modelling for beginners
OUTLINE
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
GEOMETRICAL SETTING
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
GEOMETRICAL SETTING
Topography in computational model
Dredged fairway
Groyne
Dunes
(depth 3 – 6 m)
Sheet pile walls
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
MEASURED DATA
Measured flow field
• Size of eddy is discharge independent
• Flow velocities increase with discharge
950 m³/s 1700 m³/s
1950 m³/s 840 m³/s
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SCALE MODEL
4 km of river stretch = 67 m of model length
Length Scaling: 1:60
Height Scaling: 1:30
Stationary discharge conditions, non-movable gravel bed
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SCALE MODEL
Measured flow field (surface velocities, 2D particle tracking)
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
NUMERICAL MODEL
• 11 km long river model
• Grid types:
• Quadrilateral (dx=2m),
river axis aligned,
# of elements: ~ 800.000
• Triangular (dx=1,5m),
# of elements: ~ 2.500 000
• Discharge at inflow: 986 m³/s
• Water level at outflow: 4.71 m
• Advection scheme:
Upwind Perot (2 types)
• Range of horizontal viscosities
• Smagorinsky off/ on
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
CONCLUSION 2013
The modelled flow field in the junction domain is sensitive to:
Advection scheme
Constant viscosity
Grid type
„Smagorinsky“
Lower velocities in
the eddy field
Numerical diffusion
„physically correct“?
Arguably improved?
Grid-dependent
results
Advection scheme
= crucial choice!
Grid-dependent
results
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
CONCLUSION 2013
The modelled eddy system in the recirculation zone is well represented in
• position,
• size,
• flow velocities
Best modelling result Scale model
1.0*10-6, Perot 3, Smag Field measurement
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
CONCLUSION 2013
Best modelling result
• Excellent validation case for modelling mesoscale horizontal recirculation
• Unique combined set of field data, scale model and numerical model data
Scale model
Field measurement
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
CONCLUSION 2013
• Excellent validation case for modelling mesoscale horizontal recirculation
• Unique combined set of field data, scale model and numerical model data
=> We follow the project with the new D-Flow FM engine of Delft3D Flexible
Mesh for studying purposes
Best modelling result
Scale model
Field measurement
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
CHANNEL MOUTH RE-DESIGN
…and we follow.
BAW-project continues with geometry studies accompagnied by Telemac2D-model
and the scaled model…
?
Sedimentation wedge
removed
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
CHANNEL MOUTH RE-DESIGN
Sedimentation wedge in
the up-stream part of the
mouth
Sedimentation wedge
removed
BAW-project continues with geometry studies accompagnied by Telemac2D-model
and the scaled model…
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
CHANNEL MOUTH RE-DESIGN
Result for final step
Low
da
ta d
ensity
in lab.
Meas.
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
CHANNEL MOUTH RE-DESIGN
Time averaged computed flow field
Low
da
ta d
ensity
in lab.
Meas.
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
CHANNEL MOUTH RE-DESIGN
• „Best result“ model settings deliver good results for geometry
variation
• Time dependent processes need to be taken into account
Lab. Meas. 2D-PTV Time averaged Result for final step
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
CHANNEL MOUTH RE-DESIGN
• „Best result“ model settings deliver good results for geometry
variation
• Time dependent processes need to be taken into account
Singular time step Lab. Meas. 2D-PTV Time averaged
So far, so good!
BUT:
Do we have the right results for the
right reasons?
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
Do these sheet pile walls have any influence on
the flow field?
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
Photo-grammetric measurement of topography in scaled model Sheet pile wall in scaled model
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
Photo-grammetric measurement of topography in scaled model Sheet pile wall in scaled model
What is the influence of the sheet pile wall
(rough!) on the flow field?
Location of
detachment
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
Photo-grammetric measurement of topography in scaled model
Experiment: Flat/ smooth wall instead of sheet pile wall
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
Results from scale model - 2D-PTV
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
• Higher velocities on the west side
• Extends more into the mouth
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
• Higher velocities on the west side
• Extends more into the mouth
Detachment of the flow triggered by
wall roughness!
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
RESULTS – Influence of grid type for advection scheme “Perot 3” – quads vs. triangles
Triangles
Quads
Reference data set
1.0*10-4
1.0*10-4
0 1.0*10-4
0 1.0*10-4
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
RESULTS – Influence of grid type for advection scheme “Perot 3” – quads vs. triangles
Triangles
Quads
Reference data set
1.0*10-4
1.0*10-4
0 1.0*10-4
0 1.0*10-4
? 1 + 1 = ?
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
Less grid-induced wall-friction with
triangular grid leads to good
agreement with smooth wall case
Accidently very good agreement with
roughness of sheet pile wall in
nature due to grid design
Scaled Model Scaled Model Delft3D FM Delft3D FM
SHEET PILE WALL MODELLING FOR BEGINNERS
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
Grid structure combined with
topography may provide you with
„numerical physics“!
First
lesson
learned
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
Conveyance approach
set to „3“
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
Conveyance approach
set to „0“
Conveyance approach
set to „3“
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
Seemingly harmless and well-
meant model settings – applied
outside the foreseen range of
applicability - may cause
unexpected effects !!
Second
lesson
Learned
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
THE END
Thank you for your attention
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS
Mesoscale horizontal flow-field modelling at a channel-river-junction Hydraulic Engineering · W2 · R. Patzwahl, F. Platzek, J.A. Jankowski · 5th november 2014
SHEET PILE WALL MODELLING FOR BEGINNERS