Research topics

The increasing amount of computer power makes is nowadays possible, to simulate flows in high resolution including many individual particles with proceeding exactness.

Particles in flows can be moved by suspension or saltation. An example for suspensions in the technical area are the ashes clouds attracting increased attention when the volcano Eyjafjallajökull erupted and disturbed the air traffic. The dilute fluid can massively damage the engine because of erosion and vitrifaction.

Very small particles are described by point-forces with the Maxey-Riley equation. If on the other hand the size of particles cannot be assumed to be small, the Maxey-Riley equation cannot be used und one has to simulate the flow around the particles. In saltation and reptation, e.g. if a particle hits the ground and bounces off an another one, the new particle gets airborne and the fluid or gas accelerates it. Here finite-size particles have to be used in order to model the dynamics correctly. A practical example are ballast flights for high speed trains. Many researches show that particles accumulate in boundary layers, so that particle-particle collition (called a four way coupling) is frequent. To simulate this problem an efficient four way coupling is vital. Our studies focus on the acting forces of point-particles and finite-size particles in shear layers.

Current Projects

• Particel-Laden Flow , Investigation of Particle-Laden Flow with the Lagrange-Eulerian Approach
  Flavia Cavalcanti Miranda
  
  
• Vulcanic Eruptions , The significance of the opening angle of pyroclast ejection during explosive volcanic eruptions
  Kueppers, Alatorre, Sesterhenn, Dingwell
  
  
• Vulcanic Jets , Direct Numerical Simulation of (pocket size) vulcanic jets
  Sesterhenn, Miranda, Pena-Fernandez