Category Archives: Aeronautics
On the On-Set of Hypersonics
Almost everyone has their own definition of the term hypersonic. If we were to conduct something like a public opinion poll among those present, and asked everyone to name a Mach number above which the flow of a gas should properly be described as hypersonic there would be a majority of answers round about 5 …
Congratulations to Dr. Jianhui Cheng on Defending her Ph.D.
I’m pleased to see my student Dr. Jianhui Cheng defend her Ph.D. successfully at University of Florida. Title: THE APPLICATION OF INSTABILITY WAVE THEORY ON ACOUSTIC RADIATION WITHIN OFF-DESIGN SUPERSONIC JETS AND ON TWO-POINT STATISTICS WITHIN HIGH-SPEED FLOW OVER SHARP AND BLUNT CONES WITH PLASMA ACTUATION Abstract: The intense noise generated by large-scale turbulent structures …
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On Gasdynamics
The information needed by design engineers of either aircraft or flow machinery is the pressure, the shearing stress, the temperature, and the heat flux vector imposed by the moving fluid over the surface of a specified solid body or bodies in a fluid stream of specified conditions. To supply this information is the main purpose …
On Aerodynamics
The whole problem of aerodynamics, both subsonic and supersonic, may be summed up in one sentence: Aerodynamics is the science of slowing-down the air without loss, after it has once been accelerated by any device, such as a wing or a wind tunnel. It is thus good aerodynamic practice to avoid accelerating the air more …
Wright’s Split Flap Patent
Sheet I of the U.S. Patent 1,504.663, by Orville Wright and J. M. H. Jacobs, illustrating their concept of a split flap.
On Transition
He was introduced to the sensitivity of stalling characteristics of wings to the boundary layer state near the suction peak by a change in paint scheme! The XBT-1 a forerunner to the famous SBD Dauntless alrcraft had good stall characteristics. The XBT-2 had exactly the same wing but had an unacceptable stall. The XBT-1 wing …
Development of Flaps
Original flap development was motivated by three desired benefits. 1) slower flying speeds, hence shorter takeoff and landing runs; 2) reduction of angle of attack near minimum flying speed; 3) increase of drag, or control of drag, in order to steepen glide angle in approach and reduce floating tendencies. Currently, because of large aircraft noise …
Thomas D. Norum
My good friend Thomas D. Norum recently passed away. He worked as a researcher at NASA Langley over most of his career. I knew him starting in 2009 through 2016 while I was working there. He worked as an experimentalist in the jet noise lab of NASA Langley. As an experimentalist, he worked to understand …