e-Science in fluid mechanics

Development of numerical algorithms is critical in successful e-Science based research, often matching or outperforming improvements of hardware in terms of speed gains, in particular in areas at the forefront of research which have only recently become amenable to computer simulations.

 

Micro and complex fluids

Presently there is a strong trend towards miniaturizing equipment for chemical analysis and synthesis. This is made possible by development of technologies for fabricating small-scale structures that will serve as the components of a laboratory, such as pumps, valves, reactors, separators, etc, i.e. the lab-on-a-chip concept, where all of the components are built in a single device.

Stability and transition

One of the oldest areas in fluid dynamics is that of stability of laminar flows and the breakdown to turbulence in wall bounded flows. In 1883 Osborne Reynolds performed a famous pipe flow experiment investigating the stability and transition of that flow. Theoretical approaches, which were formulated around 1910, could predict exponential instabilities, but utterly failed for the pipe flow experiment, since no exponential instability exists for that case.

Low-Mach number aeroacoustics

Until today, most aeroacoustic research has focused on aeronautical applications where high-frequency sound is the dominating issue. For low-Mach number aeroacoustics, the focus is naturally on lower frequencies, for which the coupling between the acoustic source and the surrounding geometry is stronger compared to the high frequency case. This implies that more details of the geometry need to be included.

 

Flow control and optimization

A new challenge for fluid dynamics research is to take the step from analyzing and predicting the flow field to actively controlling it. In many fluid-mechanics systems, significant variations of global flow parameters may be achieved by local perturbations using devices sensing and acting on some critically chosen parts of the flow, the process often requiring small amounts of energy.

 

High Reynolds number turbulence including geophysical flows

Hydrodynamic turbulence is the archetype of highly nonlinear chaotic systems possessing many degrees of freedom and a wide span of scales. As such, it has often been described as ”the last unsolved problem of classical physics”.