Work Programme

Thematic Focussing

Based on the definition of the projects MetStroem concentrates on three areas of application which register exemplarily the challenges of multi-scale modelling.

Scale-separated phenomena

In many meteorological and fluid-dynamical processes gravity waves, inertial and compressional waves interact with vortices as well as with drop and particle clouds on different scales. Modelling and numerical approaches which are tailored to the exposition of scale-separated phenomena can be tested by that.

Typical examples in fluid dynamics and meteorology:

• Excitation of gravity waves and compressional waves by small-scaled vortices or processes of reaction or condensation
• Interactions of meso-scaled gravity waves with meteorological depression areas and tropical cyclones

Large scales of turbulence

In boundary layers over complex boundaries the fluid-dynamics on the length scale of the larger geometrical elements interacts with turbulence generated by those elements. Such processes demand an approach which is able to register the diffuse transition of quasi-deterministic fluid mechanics above the integral turbulence length to the chaotic fluctuations below the same.

Typical examples in fluid mechanics and meteorology:

• Transition of Reynolds-averaged turbulence modeling to Very Large Eddy Simulation and Large Eddy Simulation
• Accumulation of wind fluctuation above urban areas results in effective vertical energetic and impulsive fluxes

Small scales of turbulence

Also on small scales one finds multi-scaled mass exchange, impulse exchange and energy exchange. The consideration of small particles or drops in a buoyancy subjected fluid requires closure models which couple the particle dynamics with the smallest scales of the turbulence on two sides.

Typical examples of fluid mechanics and meteorology:

• Spray dynamics and Spray combustion
• Turbulence-structured movement of hydrometeors in clouds.