Wind-induced limitations at a new airport in Greenland

Terrain-induced turbulence and windshear can be a problem for the airports in Greenland. A windtunnel test can address where and when the challenge from the wind will be at an acceptable level.

In 2015, Greenland’s Parliament voted in favour of upgrading the country’s airport infrastructure. This includes extension of the runways at both Nuuk Airport and Ilulissat Airport as well as establishing a new airport at Qaqortoq.

Qaqortoq (formerly Julianehaab in Danish) is the most populous town in southern Greenland. Currently Qaqortoq is air-serviced by a helicopter link to Narsarsuaq Airport from where destinations in the rest of Greenland and in Europe can be reached.

Initially several locations for the Qaqortoq Airport were considered, but finally the location referred to as ”Storefjeld” was chosen. Due to the hilly surroundings, however, this location poses a challenge in terms of wind conditions and turbulence.

We have previously performed numerical investigations of the wind conditions for the proposed layout of the new airport. These investigations have now been followed by more detailed wind tunnel investigations of the turbulence conditions for approaching aircrafts.
The investigation was contracted by Kalaallit Airports A/S. Inuplan A/S acted as the client’s consultant regarding the present investigations.

A model in a 1:1500 scale

A very large terrain model of an area of approximately 15 by 20 km2 was constructed in scale 1:1500 based on digital maps. The model was installed in our wide boundary-layer wind tunnel and exposed to wind from the known frequent wind directions. The variation of the wind speed experienced by the landing aircraft along the approach path was measured by means of a 3D probe traversed along the approach route at the correctly scaled speed for a number of wind speeds.

By applying recognised rules, the measured wind speed gradients were converted to the level of turbulent response of the aircraft, and the limiting wind speeds for the occurrence of severe turbulence were established for the different wind directions. By combining these limiting wind speeds with the wind statistics for the airport, the impact of terrain-induced turbulence on the regularity was determined.