Wind Loads Analysis

Being located in the sunny state of Florida, we are well equated with the strong winds that accompany hurricanes. One of the ways CFD can be used is to provide structural engineers with the boundary conditions they need to understand whether or not their structure will be able to withstand such strong winds. To illustrate the benefit of such an analysis, we selected three well-known tall buildings in the state of Flordia and looked to see how high the pressure on each might be due to the strong winds associated with a hurricane.

Cinderella’s Castle

One of the most iconic structures in all of Florida is the home where Cinderella lives. Her castle, modeled after an actual castle in Germany, includes several tall spires that are cylindrical in shape. Such structures can be problematic in high winds because the shredding vortices and create an oscillating forcing function that might cause the cladding to break free or maybe even do structural damage in the form of fatiguing the structure over an extended period of time.

Velocity contours
Pressure Contours

Panorama Tower

Miami has several iconic tall buildings, but one of the most impressive is the Panorama Tower. It stands right on the edge of the coastline where the strongest hurricanes first make landfall. It is surrounded by its smaller siblings like a general leading its troops into a head-long battle with the hurricane. But the Panorama tower, standing much taller than its friends, will still need to be able to withstand the full force of the hurricane at its highest floors.

Velocity contours
Pressure Contours

Hard Rock Hotel

If you want to go against the architectural guideline of form follows function, then there is no better way to do so than to build a hotel in the shape of a guitar. However, if you are Hard Rock Hotel and Casino in Hollywood Florida, then you could make the case that its function is to represent rock and roll, and what better way to do that than to build a guitar-shaped hotel. The only problem is that Hollywood Florida is in south Florida near the coast, and hurricanes have been known to pass that way. So that begs the question, how would a guitar-shaped hotel that presents such a large, flat, glass surface to winds of any strength fair in the midst of a hurricane that produces winds of 150 mph.

The first figure shows that the large flat frontal area of the building would result in a very high-pressure load on the windows on the windward side.

Pressure Contours

The next figure shows the effect of the building’s shape on the wind speed as it approaches and passes around the building. The large blue region behind the building is where the flow velocity has dropped considerably lower than the average velocity of the hurricane itself. This might result in a suction effect on the windows on the downstream side of the building, and if the flow were to set up a fluctuating pattern of separating and reattaching to the surface of those windows, it could create an oscillating forcing function effect that might weaken the fasteners holding those windows in place, causing them to become displaced, allowing water into the building resulting in water damage.

Velocity Contours

The next figure shows a different view of the velocity contours around the building at its top where the fin type structures are located. From this figure, we can see that the wake of the flow around and through the fins on the upstream side of the building impacts and passes over the fins on the downstream side of the building. This fact is not that compelling from viewing this result, but if we were to rerun the same model as a transient solution and were able to resolve the effect of vortices shedding off of the upstream fins, it would be interesting to see how, if at all, those vortices impact the downstream fins. If the impact were to be significant, and were to occur at a frequency that excited the structures of the downstream fins, it might lead to structural damage. This is another example of the benefit gained by doing detailed CFD models to predict the wind loads tall buildings would experience during a typical hurricane.

Velocity Contours

We hope you have found these examples informative. If you are in the process of planning the construction of a tall or large structure in the sunny state of Florida, or another area that experiences Hurricanes, and would be interested in speaking with us about possibly having us complete a CFD model to predict the wind loads on your building’s design, please submit the contact form below and we will be glad to speak with you.

Notice: The models used in these examples were constructed using images available on the internet, and are not based on actual models of the actual builds.  These results are merely meant to serve as an illustration of the type of detailed information that could be obtained using CFD for wind load analysis of tall builds, and should not be taken as actual results for the buildings mentioned.