# Wind Loads on a Tall Building¶

## Overview¶

The aim of this test case is to validate, with a pre-referenced case [1], the wind pressure on a tall building using the following parameters:

- Static Pressure Coefficient distribution on the windward, lateral and leeward side of the building
- Static Pressure Coefficient distribution over the building perimeter at ⅔ of the building height.

The aforementioned parameters are obtained performing a temporal averaged mean of the values, calculated with a transient incompressible flow analysis. The simulation was executed with Pacefish®.

## Geometry and Computational Domain¶

The building model has a rectangular prismatic shape with dimensions 45.72 (m) by 30 (m) by 182.88 (m) height. The computational domain dimensions are 1485 (m) in streamwise direction, 450 (m) in spanwise direction and the total height is equal to 364 (m).

The mesh was generated with local refinements near the building walls, as well as for the ground in order to model properly the boundary layer behaviour. The region refinement is also extended downstream to capture the flow separation behind the building.

The inlet, lateral and downstream boundaries are extended laterally to minimize blockage issue on the aerodynamics of the test building. The mesh size is about 35 millions, made up by 3D hexahedrons.

## Simulation Setup¶

Air with kinematic viscosity of \(1.5 \times 10^{-5} kg/ms\) and density of \(1.2 kg/m^{3}\) is assigned as the domain fluid. The boundary conditions for the simulation are shown in following table.

Parameter | Top, left and right faces | Inlet | Outlet | Building walls and ground |
---|---|---|---|---|

Velocity | No Slip | Velocity Profile | Zero Gradient | 0 [m/s] |

Pressure | Zero Gradient | 0 [Pa] | Zero Gradient | Zero Gradient |

Turbulent intensity | / | Turbulent Intensity Profile | / | / |

Simulation Run Time: 1.75 -2 hrs on 4 GPUs

The Fig. represents the inflow velocity profile used in the present study. The inlet Turbulence Intensity profile is obtained from the reference [2].

## Results¶

For validation and comparison purposes, measurements of mean static pressure normalized by the dynamic pressure, with a velocity of \(12.7 m/s\) (at the building height), are compared with the data obtained from [1]. The mean static pressure coefficients, Cp, on the upper windward, sidewall and leeward faces are extracted for the isolated building case at \(2/3\) of the height of the building. There is a good agreement between the present results of the current study with the numerical and experimental results.

Contour plot of mean static pressure coefficient (Cp) over the building walls (windward and leeward faces) compared with [1] as reference.

Instantaneous velocity contours, side and top view.

## References¶

[1] | (1, 2, 3) `Agerneh K. Dagnew, Girma T. Bitsuamalk, Ryan Merrick, Computational evaluation of wind pressures on tall buildings, Americas Conference on Wind Engineering, June 2009.`_ |

[2] | `Agerneh K. Dagnew, Girma T. Bitsuamalk,Computational evaluation of wind loads on buildings: a review, Wind and Structures, Vol. 16, No. 6(2013) 629-660`_ |