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 …
Category Archives: Aeronautics
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 …
Sonic Boom for Lilliputians
Numerical prediction of loudness metrics for N-waves and shaped sonic booms in kinematic turbulence
Abstract, “The effects of a kinematic field of velocity fluctuations on the loudness metrics of two waveforms are examined with a three-dimensional one-way propagation solver. The waveforms consist of an N-wave and a simulated low-boom from NASA’s X-59 QueSST aircraft. The kinematic turbulence is generated using a von Karman composite spectrum, which is dependent on …
AEDC von Karman Facility
Variable Density Wind Tunnel
When visiting NASA Langley I had Josh Blake kindly take my picture by the Variable Density Wind Tunnel. Pioneered by Max Munk, leading theoretician in aerodynamics in America in our early years of aviation. National historical landmark: The test section and airflow passages built into the VDT pressure vessel formed a continuous flow of pressurized …