Willkommen am Lehrstuhl für Aerodynamik und Strömungsmechanik

Numerical modeling, simulation and experimental analysis of fluids and fluid flows

The focus of the Institute of Aerodynamics and Fluid Mechanics in 2017-18 continued on further development of a multi-resolution parallel simulation environment for the NANOSHOCK project, on reduced-order modeling of fluid-structure interaction, on the analysis of advanced aerodynamic configurations for helicopter, aircraft and automobiles, and on advanced simulation and gridding technologies for exterior and interior aerodynamics. A new focus has been placed on learning effective evolution equations from data and physical knowledge, in cooperation with George Karniadakis who received the Humboldt research award in 2018.

A highlight in 2017-18 was the publication of a paper on bubble-collapse-driven penetration of biomaterial-surrogate liquid-liquid interfaces by Shucheng Pan, Stefan Adami, Xiangyu Hu and Nikolaus Adams, which was made the ‘editor’s choice’ of Phys. Rev. Fluids. Nikolaus Adams was appointed as consultant professor and faculty member of the Northwestern Polytechnical University in Xi’an. Updates on the NANOSHOCK open-source code development are available for the scientific community: www.aer.mw.tum.de/abteilungen/nanoshock/news

 

Experimental Investigation of Shock-induced Droplet Break-up and Numerical Simulation of Collapsing Clouds of Vapor Bubbles

Collapsed and partially
rebounded vapor bubbles
and vapor pattern located at
a solid surface (bottom). The
colors indicate the shock-wave
intensity due to prior collapse
processes.

Motivation and Objectives

The break-up of liquid droplets and fluid ligaments in a gaseous ambience is a key element of atomization processes. In combustion engines, the quality of the spray inside the combustion chamber has a large impact on the combustion efficiency and also on size and composition of particles in the exhaust gas. Furthermore, droplet break-up can play an important role in the production of metal powders as used for additive manufacturing. In this case, liquid metal atomization needs to be controlled in order to optimize the quality of the resulting powder. Our objective is to gain insight into break-up mechanisms by investigation of Newtonian and non-Newtonian liquid drops exposed to shock waves generated by a shock tube. >> mehr lesen

NANOSHOCK* – Manufacturing Shock Interactions for Innovative Nanoscale Processes

Shock-bubble interaction of an air-helium interface: 3D visualization of the late stage interface deformation at LRZ.

Motivation and Objectives

We want to investigate the potential of shockwaves for in-situ control of fluid processes with surgical precision. Shockwaves are discontinuities in the macroscopic fluid state that can lead to extreme temperatures, pressures and concentrations of energy. Applications of such shock interactions range from kidney-stone lithotripsy and drug delivery, to advanced aircraft design. With the use of properly focused shockwaves on tissue material, e.g. lesions with unprecedented surgical precision can be generated. Alternatively, improving combustion  >> mehr lesen

Aircraft and Helicopter Aerodynamics

Computed (left) and measured (Stereo-PIV measurements for inhomogeneous inflow, right) propeller flow field.

Motivation and Objectives

The long-term research agenda is dedicated to the continued improvement of flow simulation and analysis capabilities enhancing the efficiency of aircraft and helicopter configurations with respect to the Flightpath 2050 objectives. Aircraft aerodynamics research is aimed at detailing flow physics understanding of leading-edge vortex evolution (DFG) and vortex interaction effects (DFG) along with diamond wing aerodynamics and turbulence model conditioning (VitAM, LuFo V-3). Analysis of fluid-structure-interaction effects and aeroelasticity is linked to elasto-flexible lifting surface characteristics (DFG), >> mehr lesen

Reduced Order Modeling for Automotive Aerodynamics

40% scale DrivAer model (notchback configuration) in wind channel A

The recent improvement of high-performance computing hardware has enabled the utilization of unsteady computational fluid dynamics (CFD) for industrial product development. Unsteady CFD can accurately simulate the transient phenomena of the flow field, moreover, highly accurate steady-state results can also be obtained through appropriate averaging. Especially in the field of automotive aerodynamics, the transient flow phenomena around the vehicle can strongly affect driving stability and ride comfort. A difficulty in the analysis of the transient flow field by CFD >> mehr lesen

Numerical Investigation of Homogeneous Cavitation Nucleation in a Microchannel

Numerical simulation of homogeneous nucleation in comparison with the experimental results.

Motivation and Objectives

Liquid and gas (or vapor) two-phase flows ar e widely encountered in many chemical, biological, and engineering applications; here bubble cloud dynamics are of fundamental importance. Examples reach from ultrasonic cleaning through medical therapy applications to bacteria disinfection processes. In such flows, bubble nucleation, initializing liquid-to-vapor transition, can be categorized into heterogeneous and homogeneous nucleation. These differ with respect >> mehr lesen

Laminar-turbulent Transition with Chemical (Non-)Equilibrium in Hypersonic Boundary-Layer Flows

Integration domain on a re-entry capsule

Motivation Blunt bodies returning from space are subject to immense heat loads leading to ablation. Roughness on these ablating surfaces can induce laminar-turbulent transition in an otherwise laminar flow. Laminar-turbulent transition increases the heat load on the surface. Roughness is an enhancing effect on laminar-turbulent transition and the effect of roughness including dissociation and non-equilibrium effects is the focal point of the studies. >> mehr lesen

DFG Sonderforschungsbereich TRR 40: Technological Foundations for the Design of Thermally and Mechanically Highly Loaded Components of Future Space Transportation Systems

Instantaneous snapshots of a nitrogen jet in hydrogen: (a) temperature, (b) vapor fraction on a molar basis, (c) hydrogen density and (d) relative difference in density.

The Institute of Aerodynamics and Fluidmechanics has the speaker role within the DFG-SFB TRR40. Next-generation space transportation systems will be based on rocket propulsion systems which deliver the best compromise between development and production cost and performance. The TRR40 >> mehr lesen

SPH Modeling of Fluid-Structure Interaction

The sequence of results (ordered left to right and top to bottom) shows an SPH simulation of a tethered fish flapping in a stream with a Reynolds number of 1,000. An inextensible rope is connected to the left boundary. The color presents velocity magnitude of the fish body and vorticity in flow.

Motivation and Objectives

Fluid-structure interaction (FSI) can be found in many natural phenomena, such as birds flying and fish swimming. Meanwhile, it also plays a very important role in a wide range of engineering areas, e.g. aeronautical engineering, coastal engineering and biomedical engineering. The essential of FSI is the interaction between movable or deformable structures with internal or surrounding fluid flows. >> mehr lesen