Periodic Reporting for period 4 - NANOSHOCK (Manufacturing Shock Interactions for Innovative Nanoscale Processes)
Période du rapport: 2020-06-01 au 2020-11-30
Main methodological accomplishment is a new advanced numerical-simulation framework that is capable of predicting highly complex interface interaction mechanisms with discontinuous flow states. The accuracy and level of detail that is achieved with high-fidelity simulations allows to complement and enhance experimental investigations by the ability for non-invasive quantitative data analysis and targeted parameter studies. With the help of highly resolved numerical simulations, we have been able to identify new interface deformation mechanisms (e.g. new aerobreakup mechanisms, previously unkown phenomena during the collapse of triple-emulsion structures). We are currently further exploring the wealth of new findings and the new opportunities opened by their understanding for future technical and medical applications.
As of flow-physics investigations with ALPACA, we have studied fundamentals of shock-induced bubble collapse dynamics near biomaterial-surrogate gelatin interfaces. This ongoing research helps to understand perforation of living cells, as it occurs e.g. during sonoporation (transient increase of cell permeability with improved drug uptake). Within the last reporting period we have identified a novel flow focusing mechanism that can be technically exploited for non-invasive surgery on cell level or enhanced drug-delivery. Shock-driven interface breakup, surface cleaning, high-viscosity micro-jetting, and liquid-drop explosion phenomena have been investigated with ALPACA revealing an unprecedented level of detail. Results corroborated experimental finding, revealed much of hidden insight, and also falsified erroneous experimental claims. The high quality level of resulting publications demonstrates the value of numerical simulations to the scientific community.
In order to reduce simulation costs of complex flow problems, we have been developing approaches towards the inverse problem. Here, the idea is to understand the sensitivity of the simulation result on the input parameter to define a specific initial setting for a desirable outcome. With these methods, shock-bubble interactions can be manufactured, e.g. to control the peak pressures at a given location in time for complex configurations where explicit numerical simulations would be tedious, if not infeasible.
To reach out to the broader public and to literally visualize our simulation results, we have developed a transformation of flow simulation data to Virtual Reality in collaboration with the Centre for Virtual Reality and Visualization (V2C, LRZ Garching). We can offer now to ""experience"" three-dimensional simulation results, for instance by fly-through of a collapsing helium bubble in air."
We have discovered previously unknown breakup mechanisms during the shock – interaction of a triple-phase emulsion drop, which mimics a layered-capsule / nanoparticle as used in modern medical applications. The resulting highly focused and shielded micro-jet of the inner material could be very useful for future targeted drug delivery. The investigation of droplet breakup under extreme conditions has demonstrated the potential of numerical simulations for complementing experimental investigations. With the help of a novel Knudsen-front Riemann solver for the conservative interface-interaction method (level set method), we have been able to simulate phase transition through rapid evaporation for a laser-induced shock-driven explosion of an isolated liquid drop.