Timeline

14:00-15:00	BMS Friday Colloquium: Anomalous random walk and diffusion in random media (Professor Takashi Kumagai)
15:15-15:20	Opening of the 2019 Richard-von-Mises-Lecture
15:20-16:00	Historical Talk: Wind tunnels - indispensable means of aerodynamic research (Dipl.-Ing. Hans-Dieter Tack)
16:00-16:30	Coffee Break
16:30-17:30	Richard-von-Mises-Lecture: Stochastic dynamics and stability of aerospace systems (Professor Sri Namachchivaya)
17:30-18:00	Reception and Get-Together

Abstracts

Stochastic dynamics and stability of aerospace systems
Professor N. Sri Namachchivaya (University of Waterloo)

I will present a general overview of several engineered and natural systems with uncertain mathematical models, the multidisciplinary methods (that encompass the area of random dynamical systems) required for their analysis, and relevant results. The first part of this talk focuses on developing methods to unravel complex interactions between noise and nonlinearities using a mix of multidisciplinary approaches from theory, modeling, and simulation. Practical applications of these research results are beginning to appear across the entire spectrum of mechanics. I will examine the flutter characteristics of an airfoil in turbulent flow. Turbulence is a common factor in airplane accidents, for example loss of in-flight control associated with wind gusts, which can cause substantial damage to the aircraft and injuries to crew and passengers. The analysis is performed close to the critical value of the bifurcation parameter (the free-stream airspeed) that induces flutter in a two-dimensional airfoil. The second part of the talk focuses on the challenges in data assimilation that arise from the interactions between uncertainties, nonlinearities, and observations. I will present rigorous reduced-order data assimilation techniques for high dimensional multi-scale problems. In particular, I will outline how scaling interacts with filtering via stochastic averaging. Finally, I will present a new particle filtering algorithm that combines stochastic homogenization with filtering theory, where importance sampling and control methods are used as a basic and flexible tool for the construction of the proposal density inherent in particle filtering.

Wind tunnels - indispensable means of aerodynamic research
Dipl.-Ing. Hans-Dieter Tack

The aim of the presentation is to give an overview of the use of wind tunnels for aerodynamic investigations of missiles of all kinds. The development of the first, still very simple plants of this kind go back to the end of the 19th century in England. Only with the development of the flying machine did the first aerodynamic investigations become the subject of aviation research. Already Otto Lilienthal experimented with first systems, but still in the form of a simple so-called rotary apparatus. The first viable wind tunnel was built in the course of the trials in preparation for the first flight of the Wright brothers. The most important impulses for the large-scale use of wind tunnels came from the German Ludwig Prandtl (principle of the closed circuit of the air) and the Frenchman Gustave Eiffel (closed construction method). At the beginning of the 20th century, the era of using wind tunnels began for different research purposes. Characteristic until the time after the Second World War is the construction of large aviation research centers, combined with the use of wind tunnels of different design and performance parameters. This happened mainly in the US, Britain, France, Italy, Japan, the Soviet Union and Germany. This is done in conjunction with references to specific facilities and their current state of preservation. The following is an overview of the operation of the two basic types and the methods of research.
After the lecture there is the possibility to visit the Messhalle and the large wind tunnel and the Trudel wind tunnel of the former large research institute German research institute for aviation DVL at the location Berlin Adlershof.