S. A. E. Miller, Ph.D.

I was recently awarded the 2015 NASA Early Career Achievement Medal. The official NASA photo was recently released. The medal is for my work in theoretical aeroacoustics and its application to jet noise prediction.

I have begun a new journey in the field of combustion. Currently I am reviewing flammability limits, heat release, flame extinction, acoustics, etc. There is some limited literature on acoustic waves from combustion. I am hopeful that I might eventually place these papers on a more grounded theoretical basis. Current models in use are mainly almost empirical in nature or entirely computational. It seems that the field is open to a more advanced mathematical model.

This weekend I was able to visit the Artist’s Garden Exhibit at The Chrysler Museum of Art in Norfolk Virginia. The exhibit is open until early September. Approximately seventy works are on display. This space shows American artists that used gardens essentially as laboratories for their studies in color theory in the impressionist style. Those who are regular visitors will certainly reconize some of the American artists by name and perhaps style. I certainly discovered a few new favorites. The growth of the American middle class in the late 19th century was able to have and explore gardens. A theme emerges in the exhibit of showcasing feminity within the walled garden. In my view many of the artists saw their female models as idealizations within the walled garden. Exagerations are present in some of the work of both the flowers (eg: painted larger and more vivid) and the models aesthetic ideal of the time-period. Nonetheless, the works are inspiring, and I will certainly be going again and again.

My good friend and colleague Alexandra sent me a picture of wildflowers near Lyon, France. I love wildflowers. Perhaps more interestingly Lyon is the location of the Aeroacoustics conference. I can imagine Camille Pissarro incorporating these into some of his countryside paintings. I think that a visit to the Norfolk Botanical Gardens is in order.

The NASA Library is amazing and provided me with the original in Russian.

Kolmogorov, A. N., “The Local Structure of Turbulence in Incompressible Viscous Fluid for Very Large Reynolds Number,” Dokl. Akad. Nauk. SSSR, Vol. 30, 1941, pp. 299–303.

It is that time of year again where the World War 2 Airshow occurs near Virginia Beach. Myself and some NASA colleauges headed down on the Saturday to watch flights from 1 pm to approximately 4 pm. It was a beautiful and sunny day. The static dispaly was fun also, including the flight line, and I lost some hearing due to the firing of an 88. There were reenactors from all countries involved (Americans dressed up as Russians, Germans, etc. really). My favorite flight was from twin jet engine messerschmitt, that was a welcome change from all the slower and perhaps less noisy props. I also enjoyed examining the Yak 3.

The American Kite Associate visited Virginia Beach recently. They had three areas on the beach fenced off. The first was for open flying. Anyone could go and fly a kite. The second was a static display of many different types of kites. I love octopus – and there were many so that made me very happy. Finally, there was a competition area for two and four string kites. The flyers tried to pair music with their kites to make a routine – think figure skating but in the area.

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 sweptback shock — swept at the same angle as the wing — i.e., it would be an oblique shock. Such an oblique shock cannot form until the velocity component normal to it becomes supersonic.

Sonnet to Turbulence
Stanley 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 maze
May give us paradigms of flows to find.
Orthonormal forms non-linearly renew
Intricate flows with many free degrees
Or, in the latest fashion, merely few
As strange attractor. In fact, we need Cray 3s.
Experiment and theory, unforgiving;
For serious searcher, fun … and its a living!

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).