Project Title:

Similarity Principles to Enable Heavy Gas Testing of High-Lift Systems at Flight Reynolds Numbers

  94-1	02.08	9457

  Similarity Principles to Enable Heavy Gas Testing of High-Lift 
  Systems at Flight Reynolds Numbers  

Abstract:

High-lift systems testing at flight Reynolds numbers can only 
be achieved in current tunnels by substitution of cryogens or 
heavy gases for the tunnel air. Productivity problems 
associated with cryogenics make heavy gases an attractive 
alternative, but because these gases are not ideal, a reliable 
method is needed for transforming viscous, compressible non-
ideal flows to their air equivalents. Nielsen Engineering 
proposes to develop the similarity principles that would make 
possible reliable transformation of test results between heavy 
gas and air. This will be achieved through application of Lie 
group methods to the compressible Navier-Stokes equations. 
Establishing these similarity laws would enable the 
development of this commercially important testing technology, 
advance the pace and accuracy of high-lift system design in 
the US, and could save both NASA and the US aircraft industry 
hundreds of millions of dollars in new facilities money.

The technology developed here would enable the development of a 
new, commercially important testing methodology for the US 
aircraft industry. Its application would advance the pace and 
accuracy of high-lift system design in the US, an area where 
European efforts are believed superior. It could also save NASA 
and the aircraft industry hundreds of millions of dollars in new 
facilities money, by allowing the conversion of existing tunnels, 
or the construction of smaller ones, to obtain flight Reynolds 
number testing ability.  

Key Words

Nielsen Engineering & Research, Inc.
526 Clyde Avenue
Mountain View, CA 94043-2212