Hello Shadab Mahdiyar,

I have recently been working on a project involving the evaluation of pressure profiles on special structures. Various countries have established standards for velocity profiles that can serve as boundary conditions for CFD analysis. These profiles are closely related to the region's topology and its surrounding areas.

Wind profiles are often modeled as power functions, and you can determine them by specifying specific data points and the ground's roughness. It's essential to consider the reference velocity at a specific height in your analysis. This reference velocity can be chosen at various heights, as long as the velocity profile remains consistent.

Please note that you can measure the reference velocity on-site, or you can use data from the nearest airports. However, when using such data, it's crucial to ensure that you are working with statistically significant long-term data. For more detailed information and specific standards, I strongly recommend referring to the ASCE7 standard.

For enclosed and partially enclosed buildings:

p=qGCp−qi(GCpi)

(1)

For open buildings:

p=qGfCp−q(GCpi)

(2)

Where:

G

= gust effect factor Cp = external pressure coefficient (GCpi)= internal pressure coefficient q

= velocity pressure, in Pa, given by the formula:

q=0.613KzKztKdV2

(3)

q

= qh for leeward walls, side walls, and roofs,evaluated at roof mean height, h q = qz for windward walls, evaluated at height, z qi = qh for negative internal pressure, (−GCpi) evaluation and qz for positive internal pressure evaluation (+GCpi) of partially enclosed buildings but can be taken as qh for conservative value. Kz = velocity pressure coefficient Kzt= topographic factor Kd= wind directionality factor V = basic wind speed in m/s

Determine the Velocity Pressure, qz:One of the important aspects of Wind Analysis is the velocity pressure. Regardless of which analysis approaches we may use, velocity pressure is a requirement. The velocity pressure is depending on wind speed and topographic location of a structure as per the code standard velocity pressure, qz equivalent at height z shall be calculated as qz = 0.00256 Kz Kzt Kd V2 (lb/ft2) or qz = 0.613 Kz Kzt Kd V2 (N/m2); V=m/s where: Kz is velocity pressure exposure coefficient Kzt is the topographic factor Kd is wind directionality factor V is the basic wind speed Velocity pressure exposure coefficients, Kz are listed Table 27.3-1 of ASCE 7-16 or can be calculated as Kz = 2.01 (z/zg)2/αfrom which, z is the height above ground and should not be less than 15 feet (4.5 meters) except that z shall not be less than 30 feet (9 meters) for exposure B for low rise building and for component and cladding. The parameters, α, and zg are taken as follows:

📷

Topographic Factor, Kzt: Kzt = (1 + K1K2K3)2where: K1, K2, K3 are determined from Figure 26.8-1 of ASCE 7-16 based on ridge, escarpment, and hill. If site conditions and locations of structures do not meet all the conditions specified in section 26.8.1 then Kzt =1.0 Wind Directionality Factor; Kd shall be determined from Table 26.6-1 and the basic wind speed, V is according to Figure 26.5-1 of ASCE 7-16