Could wind tunnel provide accurate results to wind load distribution over the building?
What if the building is very flexible like cable stayed bridges or tall building. Could it be simulated using wind tunnel?
Dr. Khalid M., this interest question..
Yes you can do it..and doing the experimental simulation for the prototype using wind tunnel and obtained a high accurate results.
You can get accurate results but accuracy depends on the size of test section of the wind tunnel and other parameters.
Khaled. Yes, the buildings and structures you mention (and many other human constructions) are routinely studied in wind tunnels every day. Some at universities (eg UWO, CSU, TTU, UF, Monash, HKUST, etc.) and some at commercial facilities (eg RWDI, CPP, MEL, etc.). The success at modeling various actions on a small-scale model in the wind tunnel has been well-established and refined since the 1960s. There are dozens of wind-engineering societies and associations in many countries around the world (AAWE and AWES to name two I belong to) and these are all connected to the international body, IAWE. The best assessment of "accuracy" is to compare the wind tunnel with a full-scale building in the real wind. There are several good examples of this (a well-known recent example was the Texas Tech University Building that spanned work over the 1990s and 2000s, and an earlier effort in Britain called SILSOE) in the literature and, with some caveats, the agreement is really quite good between model and full scale data. The Elsevier journal called Journal of Wind Engineering and Industrial Aerodynamics has been the source of many papers in this field for over 40 years. Lots of reading for you!
Using wind tunnel to measure the characteristics of flow over building is relevant but it depends on the geometry of the building (prototype or real shape ) if you use prototype you might do what is known Dimensional Analysis. However having scale one to one to do measuring you need wind tunnel which is suitable for this scale . The obtained accuracy from wind tunnel is acceptable and you need to do in parallel cfd calculations
You should satisfy dynamic and geometric similarity for any test in wind tunnel to get accurate results.
Sercan,
Collection of cladding pressure and high-frequency balance data on small-scale models (typically in the range 1:200 to 1:500) of bluff bodies (buildings) in boundary-layer wind tunnels does typically not require Reynolds Number matching due to influence of sharp corners and edges on the flow around the building. As you correctly noted the mismatch between model-scale and prototype Reynold Number is typically a couple of orders of magnitude. Fortunately for the field of architectural aerodynamics, most building are Reynolds Number independent, provided a threshold Reynolds Number of about 50,000 to 100,000 is exceeded (see documents like ASCE Manual of Practice #67, or AWES Quality Assurance Manual, etc.). Much of this Reynolds Number independence approach has been applied successfully to building studies for decades (a classic paper by Jack Cermak's in an ASME Freeman Scholar Lecture, 1975, Journal of Fluid Engineering). There are many others that expand upon this basis of modern wind engineering, but Jack's is a great starting point. With regards to your comment on rough surfaces, that is usually only considered with strongly curved structures where Reynolds Number will impact the separation point on a curved surface; and that approach requires some skill to get right. Hope this helps, LC.
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