By simulating wind early in the design process, predicted flow behaviour will lead to a better and smarter design.
Comfort and safety
The picture above shows pedestrians trying to cross the street in front of Bridgewater Place Tower. The building in the city of Leeds, UK, has such bad aerodynamics that crossing the street is not only difficult, but also dangerous. At a point rugby-players were even hired to help people cross the street. The wind effects caused the building caused a truck being overturned by the wind in 2011, tragically killing a man. Wind speeds between 67 m/h and 79 m/h were recorded there.
The answer to such a behavior lays on basic aerodynamics. The full force of the prevailing high-speed winds at 70-100 meters height hits the side of the building and is pushed downwards (downwash) and around to the side. The building then acts like a funnel, squeezing a large volume or air into a smaller space, forcing the wind speeds to accelerate with more than 5 times. As you can see in these images:
It’s well known that the specific building design is responsible for this dangerous scenario. Architects and constructors could have avoided it by performing an accurate flow simulation in early stages of the design process. Access to reliable wind information and predicting its effects on pedestrian comfort and safety allows for design optimization. Ledges on the building side would most likely have re-directed the wind and mitigated the downwash effect.
Look how a different design choice could have changed the aerodynamics of the building. The round corner from the original design increases wind speed when the flow hits the main façade of the building:
While a sharp edge makes wind speed significantly lower:
1 - Bridge Water Place Towers, England
Total cost: 850 million dollars
32 stories for office and residential rooms
Building amendments for mitigating wind effects: 1M dollar
Underestimating wind analysis
Not only high-rise buildings are affected by aerodynamic forces. Significant wind effects can be caused by buildings not more than 50 meters high. Look at these 26 stories mixed used development in Stockholm, Sweden.
In this top view simulation video, the wind speeds up near the corners of the structure and in the passage as a result of the venture effect. Pedestrian discomfort can also be caused by turbulence such as the one that can be seen in the visualization of the simulation below.
Windy and unpleasant surroundings make pedestrians find alternative routes, which in turn reduces the number of potential customers for retail establishments in the impacted area.
The value of a property is very much based on the rental income. If the retail establishments renting premises in the building starts losing customers and revenue due to low levels of pedestrian comfort, the market value of the location will drop, which will lower the rental income and the overall value of the property.
The consequence of underestimating wind analysis during the design process can easily go unnoticed during the entire design and construction phase of a building. But sooner or later, reality hits you in the face like a cold November storm. That risk is not worth taking, considering the wind simulation tools and services available.
2 - Tuletornen, Sweden
26 stories for residential use and commercial area on ground level
Low pedestrian comfort on ground level impacts surrounding retailer’s revenue
Wind analysis can also provide input for other savings in an urban project. The Chinese skyscraper, Shanghai Tower, is well known for studying the building aerodynamics in order to increase cost efficiency while maintaining comfort and safety.
The twisted form reduces wind loads by 24% offering significant savings in overall building material. That’s a $58 million in savings.
Let’s see what the wind has to say about this design choice? The streamlined representation of the air shows that by twisting the shape, less turbulence is caused, and the wind flows without strong interruptions. Wind loads are also mitigated by the design optimization:
3 - Shanghai Tower, China
Total cost: $2.4 billion dollars
128 stories, one of the tallest buildings on earth
Savings in material due to design optimization: $58 million
Understand the wind. Use it. Don’t fight it
By simulating wind early in the design process, accurate data will lead to a better and smarter design. So, do NOT underestimate the impact of wind.
Ingrid Cloud is an affordable and automated software for wind simulations. It is used by experts in computational fluid dynamics and wind analysis as well as by non-specialists who understands the value of predicting the effects of the wind. Register an account and try one simulation for free. It’s easy, fast and accurate. We also offer expert consultation to interpret the simulation results in order to draw the right conclusions.