An Elegant Explanation of the Effect of Wing Sweepback in Delaying the Appearance of Shock Waves

Suppose a cylindrical wing (constant chord, incidence, etc.) is placed in an airstream at an angle of yaw — i.e., it is swept back. Now, even if the local speed of the air on the upper surface of the wing becomes supersonic, a shock wave cannot form there because it would have to be a …

Sonnet to Turbulence by Stanley Corrsin (1920-1986)

Sonnet to TurbulenceStanley Corrsin Shall we compare you to a liminar flow?You are more lovely and more sinuous.Rough winter winds shake branches free of snow,And summer’s plumes churn up in cumulus.How do we perceive you? Let me count the ways.A random vortex field with strain entwined.Fractal? Big and small swirls in the mazeMay give us …

Mathematical Relationships

I recently gave a talk at the NASA Langley 2015 Technical Working Group. Slides are available on my website under presentations. One interesting slide shows mathematical relationships between acoustic analogy (turbulence as a source of sound) and nonlinear propagation (Burgers’ equation).

Honoring NASA Senior Theoretical Aeroacoustician Dr. Fereidoun `Feri’ Farassat

I have recently published an article in honor of the late NASA Senior Theoretical Aeroacoustician Dr. Fereidoun `Feri’ Farassat. During the first week I worked at NASA, while I was sending a fax, Dr. Farassat literally screamed from the other end of building 1208, Is this how NASA researchers spend their time?‘ I was surprised …

Fun Abstract Mathematics Website

While browsing the Internet I found an interesting website on abstract mathematics by Professor Charles Wells. The site is organized into subsections like chapters in a book. I’m especially interested in the use of different fonts, sizes, and colors to illustrate important points. Perhaps the important points are emphasized because of the experience of the …