Search Results

2D Models

Under Construction

Ground proximity simulation

Ground proximity simulation addresses a number of phenomena experienced by objects that move on or near the ground. The presence of the ground has an important impact on the behavior of the flow over the object and consequently the aerodynamic forces. Dependent on the distance from the ground, the air circulation generated around the object is influenced. Whereas in reality the object moves in relation to the air and the ground, this is reversed in the wind tunnel where the wind moves in relation to the object and the floor. Consequently, a boundary layer is developed along the tunnel floor (and the other tunnel walls), which is not representative for the real situation. For a good simulation of the effects of ground proximity, the following experimental aspects are therefore of prime importance:

Propulsion by turbofan engines

In the conventional configurations of transport aircraft, the turbofan engines are mounted either under the wings or on the rear part of the fuselage. In both configurations the engine flow interferes with the airflow over the aerodynamic configuration of the airframe in various different manners. The engine intake and exhaust can affect the circulation around the wing section in the vicinity of the engines. The slipstream can interact with the high lift elements and the empennage of the aircraft. Those interactions can be quantitatively evaluated in the properly designed wind tunnel testing of powered models.

Dynamic testing

Dynamic testing in wind tunnels is aimed at collecting unsteady aerodynamic values like forces, surface pressures, velocities, and flow field data. The reasons might be split into four categories:

Measurement techniques

Wind Tunnels

HST

Type of wind tunnel
Closed circuit, variable density, continuous wind tunnel with slotted top and bottom test section walls (12% open)

LLF

Type of wind tunnel

LST

Type of wind tunnel
Continuous, atmospheric, low-speed wind tunnel with exchangeable test sections

NWB

From 2009 to 2010, the NWB underwent substantial refurbishment to become an aeroacoustic wind tunnel of excellent acoustic properties, while at the same time its well-known high aerodynamic qualities were preserved.