Computer simulations of cavitation-induced pressure waves and erosion of nearby solid surfaces

Location
United Kingdom
Posted
Jun 18, 2017
Closes
Jul 31, 2017
Organization Type
University and College
Hours
Full Time
Details

The objective.
The objective of this PhD project is to model cavitation erosion and assess the effect of high-temperature spots in the erosion process.

The problem.
Cavitation erosion involves various phenomena that occur at different scales ranging from the collapse of the bubble to the propagation of the shock wave into the solid structure. Computer simulation of each of these phenomena relies on different modelling techniques but no model can cover, alone, the complexity of the system under investigation and a unified computational methodology is required. At the University of Birmingham we have developed a hybrid technique (called Discrete Multi-hybrid System, DMHS) [1-2] that, by linking together different models, can reach results not attainable with each technique separately. This method has been successfully tested for a variety of multiphase systems at various flow conditions and length scales [3-5] and, in this project, will be extended to the case of cavitation erosion.

The approach.
This will be achieved by combining together smoothed-particle hydrodynamics (SPH) and coarse-grained molecular dynamics (CGMD). The SPH method, in fact, is particularly effective in modelling shock waves, while CGMD is more accurate in the calculation of shock-induced damage in solids. By combining these two techniques in a hybrid fashion, we can link the propagation of the shock wave generated by the collapse of a spherical void within the liquid and the consequent erosion caused by its impact on a solid surface. This is a clear advantage over traditional numerical techniques such as Computational Fluid Dynamics (CFD) that can only deal with the hydrodynamics of cavitation and not with the effect of hydrodynamics on the erosion of the solid surface. We will also extend the DMHS to include heat transfer and heat generation to assess the effect of temperature on the erosion process.

The candidate.
Applicants require a 2:1 or higher MEng Honours degree in Chemical or Mechanical Engineering, Physics or in a related subject area. Knowledge of C++ and programming experience is essential; specific interest or previous work in fluid mechanics and/or particle methods (e.g. Molecular Dynamics or Discrete Element Method) would be

Funding Notes

The project is funded by the US Office of Naval Research (USNO).

References

[1] Alexiadis A., (2015) The Discrete Multi-Hybrid System for the simulation of solid-liquid flows PLoS ONE 10(5): e0124678
[2] Alexiadis A. (2014) A smoothed particle hydrodynamics and coarse-grained molecular dynamics hybrid technique for modelling elastic particles and breakable capsules under various flow conditions, International Journal for Numerical Methods in Engineering 100:713–719
[3] Alexiadis A. (2015) A new framework for modelling the dynamics and the breakage of capsules, vesicles and cells in fluid flow, Procedia UTAM 16:80-88.
[4] Ariane M., Allouche H., Bussone M., Giacosa F., Bernard F., Barigou M., Alexiadis A. (2017) Discrete multiphysics: a mesh-free approach to model biological valves including the formation of solid aggregates at the membrane surface and in the flow PloS ONE 12(4): e0174795.
[5] Alexiadis A., Stamatopoulos K., Wen W., Bakalis S., Barigou M.,Simmons M. (2017) Using discrete multi-physics for detailed exploration of hydrodynamics in an in vitro colon system Computers in Biology and Medicine 81:188–198.