The U.S. space agency NASA and the German Aerospace Center (DLR) have extended an agreement to explore ways to reduce aircraft noise and accelerate research into rotorcraft.

The agencies will set up validation guidelines and identify advanced methods to predict aircraft system noise. NASA says these aircraft noise reduction technologies should be designed in an environmentally friendly way, and improve efficiency.

The two agencies will separately evaluate and test high-fidelity noise predictions on two virtual aircraft configurations, including aircraft with over-wing turbofans and another with turbofans under the wings.

Data previously collected by DLR will be used as the basis for noise prediction. As part of a related research project, NASA and DLR will create a new blade imaging technique to study airflow over helicopter blades during the flight. The tool is intended to help identify when and how the rotors cause turbulent airflow during flight.