The flow over objects, forces that act on them, as well as how they interact with the flow is observed by the researchers using a wind tunnel, which now plays a more essential role because of noise pollution. From the starting, professionals have been using wind tunnels to evaluate aerodynamic theories as well as help in the model of aircraft. For a considerable time, this has remained to be their major application.

Nowadays, the aerodynamic research has enlarged other areas such as architecture, automatic industry, education and environment, among others, which make low speed wind tunnel tests more valuable. Even if the use of CFD methods has enhanced over the years, several hours of such tests are still essential to enhance a new aircraft, wind turbine or other design that encompass complicated interactions with the flow.

Because of the raise in interest of more branches of science and industry in low speed aerodynamics and the continuous incapacity to come up with accurate solutions using number codes, low speed wind tunnels are essential and impossible to replace during research and design. One necessary feature of wind tunnels is the quality of flow inside the test chamber and performances in general.

These structures are defined by three main criteria: maximum obtainable speed, turbulence level and flow consistency. As a result, the aim of a wind tunnel in terms of design is to have a controlled flow inside the test chamber in order to attain the required flow efficiency and quality parameters. When it comes to aeronautical low speed wind tunnels, those parameter needs are exceptionally strict, which significantly increases the cost of facilities.

However, low turbulence as well as high uniformity in the flow is just needed if laminar boundary layers need to be examined. One more example of where they are used is in testing aircraft engines combustion, which needs a high-priced system that would purify air within the tunnel to keep up the same quality of air. Another important element of aircraft design is the noise footprint and oftentimes, this phenomenon can only be tested in a wind tunnel.

Concerning applications in the automotive industry, the car's aerodynamic drag is obviously extremely essential. But, due to the present high control level of this parameter as well as imposed speed limits, most efforts are aimed at reducing the aerodynamic noise. Ground effect simulation is very essential as well, which leads to highly sophisticated facilities so testing of noise production and ground effect simulation is allowed in the test section.

When it comes to architecture, because buildings are situated on the ground plus they frequently have a considerably low height, these structures are found within the atmospheric boundary layer. So, it can be challenging to simulate the equal boundary layer with respect to common speed as well as turbulence level.

Author Name: Karina Popa