Wind effect on high-rise buildings of different geometry ...Arn… · Wind effect on high-rise...
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Wind effect on high-rise buildings of different geometry: comparing CFD simulation and wind tunnel test results Results Introduction In the past, tall buildings were built with symmetric and conventional geometric shapes in order to better predict their structural behaviours. Nowadays, as engineering and architecture evolved, more asymmetric shapes are being used for high-rise buildings. The current research investigated the wind effect for a conventional square shape building and a helical shape building of similar size. Using Star-CCM+, a computational fluid dynamics (CFD) software, the force and pressure coefficients induced by different wind speeds were calculated and were compared to the existing data using wind tunnel tests. This comparison showed how the 1: 500 scale tests predicted the wind-induced pressure, drag and lift aerodynamic coefficients to full-scale computational tests and allowed for better understanding of how wind tunnel tests and CFD analysis relate to real world wind-structure interaction. These findings can contribute to wind-induced disaster risk reduction planning. Methods In order to answer the research question, the geometry of a building model previously tested in the wind tunnel (Tamura et al., 2012) was modelled as a CAD model in Star- CCM+. A square conventional building shape was selected and was compared with a helix shape . Once the geometry was created with the proper dimensions then the fluid domain was generated, which acted as a virtual wind tunnel, in order to contain the fluid flow. The mesh of calculating elements was created, with controlled dimensions, such that the mesh was very fine in the proximity of the building, to capture the complex flow formations and the generated turbulence, and was coarse far from the investigated model. The fluid properties were specified, some of these included “constant density”, “K-ε turbulence model”, and inlet velocity of 25 m/s. The simulations were run for both models in order to obtain the drag and lift coefficient for each model. The CFD results were compared to the wind tunnel test outcomes. The wind-induced pressure coefficient was plotted on the surface of the models, along with the wind velocity streamlines formed around the geometry of the building models. The average value of the stabilized CFD solution was compared to the values found in the wind tunnel study performed by Tamura et al. year 2012. Drag Coefficient Lift Coefficient Helix building current project 1.080336 0.023118 Helix building WT study (Tamura et al., 2012) 1.053 0.0793 Square building current project 1.48624 0.555209 Square building WT study (Tamura et al., 2012) 1.142 0.377 Conclusions The results obtained in the current CFD study were in good agreement with the wind tunnel test results (Tamura et al., 2012). Based on the pressure, drag and lift coefficients, it can be concluded that the helix shaped building model has better aerodynamic properties than the conventional square shaped building. Furthermore it can be concluded that Computational Fluid Dynamics (CFD) is an appropriate tool for comparing and optimizing buildings’ wind characteristics at full scale. However, because the results found did not perfectly match the wind tunnel results, CFD analysis with coarser meshes cannot be employed to substitute the standard wind tunnel tests, but this represents an ideal tool to complement the experimental tests. References Hideyuki Tanaka, Yukio Tamura, Kazuo Ohtake, Masayoshi Nakai, Yong Chul Kim, (2012) Experimental investigation of aerodynamic forces and wind pressures acting on tall buildings with various unconventional configurations, Journal of Wind Engineering and Industrial Aerodynamics 2012,179-191. By: Arnaud Vadeboncoeur Supervising professor: Dr. Elena Dragomirescu, Department of Civil Engineering, University of Ottawa Figure 1: Sketch plane Figure 3: Square building CAD drawing Figure 2: Helix building CAD drawing Figure 4: Fluid domain Figure 5: Computing mesh Figure 6: Volumetric mesh control Figure 7: Wind streamlines on helix Figure 8: Wind magnitude on square building Turning Torso, Malmo, Sweden http://bocadolobo.com/blog/architecture /25-world-tallest-skyscrapers/ -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0 500 1000 1500 2000 2500 3000 3500 COEFFICIENT OF LIFT NUMBER OF ITERATION 180 ° Helix building coefficient of lift 1 1.05 1.1 1.15 1.2 1.25 1.3 1.35 0 500 1000 1500 2000 2500 3000 3500 COEFFICIENT OF DRAG NUMBER OF ITERATIONS 180 ° Helix building coefficient of Drag 1.2 1.25 1.3 1.35 1.4 1.45 1.5 1.55 1.6 1.65 0 500 1000 1500 2000 2500 3000 3500 COEFFICIENT OF LIFT NUMBER OF ITERATIONS Square building coefficient of drag -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0 500 1000 1500 2000 2500 3000 3500 LIFT COEFFICIENT NUMBER OF ITERATIONS Square building coeffifient of lift Email : [email protected] Figure 9: Graphics of force coefficients over Iteration history
Transcript of Wind effect on high-rise buildings of different geometry ...Arn… · Wind effect on high-rise...
Wind effect on high-rise buildings of different geometry:
comparing CFD simulation and wind tunnel test results
ResultsIntroduction
In the past, tall buildings were built with symmetric and conventional
geometric shapes in order to better predict their structural
behaviours. Nowadays, as engineering and architecture evolved,
more asymmetric shapes are being used for high-rise buildings. The
current research investigated the wind effect for a conventional
square shape building and a helical shape building of similar size.
Using Star-CCM+, a computational fluid dynamics (CFD) software, the
force and pressure coefficients induced by different wind speeds
were calculated and were compared to the existing data using wind
tunnel tests. This comparison showed how the 1: 500 scale tests
predicted the wind-induced pressure, drag and lift aerodynamic
coefficients to full-scale computational tests and allowed for better
understanding of how wind tunnel tests and CFD analysis relate to
real world wind-structure interaction. These findings can contribute to
wind-induced disaster risk reduction planning.
Methods
In order to answer the research question, the geometry of a building model previously
tested in the wind tunnel (Tamura et al., 2012) was modelled as a CAD model in Star-
CCM+. A square conventional building shape was selected and was compared with a
helix shape .
Once the geometry was created with the proper
dimensions then the fluid domain was generated,
which acted as a virtual wind tunnel, in order to
contain the fluid flow.
The mesh of calculating elements was created, with
controlled dimensions, such that the mesh was very
fine in the proximity of the building, to capture the
complex flow formations and the generated
turbulence, and was coarse far from the
investigated model.
The fluid properties were specified, some of these
included “constant density”, “K-ε turbulence
model”, and inlet velocity of 25 m/s. The simulations
were run for both models in order to obtain the drag
and lift coefficient for each model. The CFD results
were compared to the wind tunnel test outcomes.
The wind-induced pressure coefficient was plotted on the surface of the models, along with
the wind velocity streamlines formed around the geometry of the building models.
The average value of the stabilized CFD solution was compared to the values found
in the wind tunnel study performed by Tamura et al. year 2012.
Drag Coefficient Lift Coefficient
Helix building current project 1.080336 0.023118Helix building WT study (Tamura et al., 2012) 1.053 0.0793
Square building current project 1.48624 0.555209Square building WT study (Tamura et al., 2012) 1.142 0.377
Conclusions
The results obtained in the current CFD study were in good agreement with the wind tunnel
test results (Tamura et al., 2012). Based on the pressure, drag and lift coefficients, it can be
concluded that the helix shaped building model has better aerodynamic properties than
the conventional square shaped building. Furthermore it can be concluded that
Computational Fluid Dynamics (CFD) is an appropriate tool for comparing and optimizing
buildings’ wind characteristics at full scale. However, because the results found did not
perfectly match the wind tunnel results, CFD analysis with coarser meshes cannot be
employed to substitute the standard wind tunnel tests, but this represents an ideal tool to
complement the experimental tests.
ReferencesHideyuki Tanaka, Yukio Tamura, Kazuo Ohtake, Masayoshi Nakai, Yong Chul Kim, (2012) Experimental investigation of aerodynamic
forces and wind pressures acting on tall buildings with various unconventional configurations, Journal of Wind Engineering and
Industrial Aerodynamics 2012,179-191.
By: Arnaud Vadeboncoeur
Supervising professor: Dr. Elena Dragomirescu, Department of Civil Engineering, University of Ottawa
Figure 1: Sketch plane
Figure 3: Square building CAD drawingFigure 2: Helix building CAD drawing
Figure 4: Fluid domain
Figure 5: Computing mesh
Figure 6: Volumetric mesh control
Figure 7: Wind streamlines on helix Figure 8: Wind magnitude on square building
Turning Torso, Malmo, Swedenhttp://bocadolobo.com/blog/architecture
/25-world-tallest-skyscrapers/
-0.15
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Email : [email protected]
Figure 9: Graphics of force coefficients over Iteration history
