192 citations · 1.5k across the 40 of their papers we have counts for
40 papers
Towards indirect assessment of surface anomalies on wind turbine rotor blades
Daniel Feldmann, Felix Oehme, Lennart von Germersheim +3
We present results from novel field, lab and computer studies, that pave the way towards non-invasive classification of localised surface defects on running wind turbine rotors usi…
Routes to turbulence in Taylor-Couette flow
Daniel Feldmann, Daniel Borrero-Echeverry, Michael J. Burin +2
Fluid flows between rotating concentric cylinders exhibit two distinct routes to turbulence. In flows dominated by inner-cylinder rotation, a sequence of linear instabilities leads…
Measurement error of tracer-based velocimetry in single-phase turbulent flows with inhomogeneous refractive indices
Huixin Li, Andreas Fischer, Marc Avila +1
Inhomogeneous refractive index fields lead to errors in optical flow velocity measurements. Former respective studies are mostly in quasi two-dimensional flows, and attribute the m…
Taylor rolls on tour: Slow drift of turbulent large-scale structures in flows with continuous symmetries
Daniel Feldmann, Marc Avila
In Rayleigh-Benard convection and Taylor-Couette flow cellular patterns emerge at the onset of instability and persist as large-scale coherent structures in the turbulent regime. T…
A single-camera synthetic Schlieren method for the measurement of free liquid surfaces
Huixin Li, Marc Avila, Duo Xu
A single-camera synthetic Schlieren method is introduced to measure the height of a dynamic free liquid surface in a container with a flat bottom. Markers placed on the bottom, see…
Statistical Analysis of Thermal Conductivity Experimentally Measured in Ethylene Glycol - Based Nanofluids
Julia Tielke, Marc Avila
We collected literature data of thermal conductivity experimentally measured in ethylene glycol-based nanofluids and investigated the influence of concentration, temperature and na…
Effects of Pore-scale on the Macroscopic Properties of Natural Convection in Porous Media
Stefan Gasow, Zhe Lin, Hao Chun Zhang +3
Natural convection in porous media is a fundamental process for the long-term storage of CO2 in deep saline aquifers. Typically, details of mass transfer in porous media are inferr…
Direct numerical simulation of two-phase pipe flow: influence of the domain length on the flow regime
Carlos Plana, Baofang Song, Marc Avila
We perform direct numerical simulations of a kerosene-water mixture in pipe flow under realistic experimental conditions by solving the Cahn-Hilliard-Navier-Stokes equations. We co…
Deformation of drops by outer eddies in turbulence
Alberto Vela-Martín, Marc Avila
Drop deformation in fluid flows is investigated here as an exchange between the kinetic energy of the fluid and the surface energy of the drop. We show analytically that this energ…
Non-modal transient growth of disturbances in pulsatile and oscillatory pipe flow
Duo Xu, Baofang Song, Marc Avila
Laminar flows through pipes driven at steady, pulsatile or oscillatory rates undergo a sub-critical transition to turbulence. We carry out an extensive linear non-modal stability a…
Effect of filter kernel on scale-energetics of near-wall turbulent structures
Daniel Feldmann, Mohammad Umair, Marc Avila +1
Inter-scale energy fluxes, , are widely used as a diagnostic tool to analyse energy transfer across length scales, , in turbulence data. Here, we investigate how the choice…
Resonances in pulsatile channel flow with an elastic wall
Duo Xu, Matthias Heil, Thomas Seeböck +1
Interactions between fluids and elastic solids are ubiquitous in application ranging from aeronautical and civil engineering to physiological flows. Here we study the pulsatile flo…
Nonlinear hydrodynamic instability and turbulence in pulsatile flow
Duo Xu, Atul Varshney, Xingyu Ma +4
Pulsating flows through tubular geometries are laminar provided that velocities are moderate. This in particular is also believed to apply to cardiovascular flows where inertial fo…
Inflow boundary conditions determine T-mixer efficiency
Tobias Schikarski, Holger Trzenschiok, Wolfgang Peukert +1
We report on a comprehensive experimental-computational study of a simple T-shaped mixer for Reynolds numbers up to . In the experiments, we determine the mixing time by appl…
nsCouette -- A high-performance code for direct numerical simulations of turbulent Taylor-Couette flow
Jose Manuel Lopez, Daniel Feldmann, Markus Rampp +3
We present nsCouette, a highly scalable software tool to solve the Navier-Stokes equations for incompressible fluid flow between differentially heated and independently rotating, c…
Topology optimization of unsaturated flows in multi-material porous media: application to a simple diaper model
Fabian Wein, Nan Chen, Naveed Iqbal +2
We present a mathematical approach to optimize the material distribution for fluid transport in unsaturated porous media. Our benchmark problem is a simplified diaper model as an e…
Phase-field simulation of core-annular pipe flow
Baofang Song, Carlos Plana, Jose M. Lopez +1
Phase-field methods have long been used to model the flow of immiscible fluids. Their ability to naturally capture interface topological changes is widely recognized, but their acc…
The effect of pulsation frequency on transition in pulsatile pipe flow
Duo Xu, Marc Avila
Pulsatile flows are common in nature and in applications, but their stability and transition to turbulence are still poorly understood. Even in the simple case of pipe flow subject…
Destabilizing turbulence in pipe flow
J. Kühnen, B. Song, D. Scarselli +5
Turbulence is the major cause of friction losses in transport processes and it is responsible for a drastic drag increase in flows over bounding surfaces. While much effort is inve…
Conditional statistics of supersonic turbulent boundary layer in the intermittent region
Xiaoshuai Wu, Jianhan Liang, Yuxin Zhao +1
The turbulence statistics of the intermittent region in a supersonic turbulent boundary layer are studied by direct numerical simulation. Recently, Kwon et al. (2016) have shown th…
Dynamo Action in a Quasi-Keplerian Taylor-Couette Flow
Anna Guseva, Rainer Hollerbach, Ashley P. Willis +1
We numerically compute the flow of an electrically conducting fluid in a Taylor-Couette geometry where the rotation rates of the inner and outer cylinders satisfy $Ω_o/Ω_i=(r_o/r_i…
Quasi-two-dimensional nonlinear evolution of helical magnetorotational instability in a magnetized Taylor-Couette flow
G. Mamatsashvili, F. Stefani, A. Guseva +1
Magnetorotational instability (MRI) is one of the fundamental processes in astrophysics, driving angular momentum transport and mass accretion in a wide variety of cosmic objects.…
Transport properties of the Azimuthal Magnetorotational Instability
Anna Guseva, Ashley P. Willis, Rainer Hollerbach +1
The magnetorotational instability (MRI) is thought to be a powerful source of turbulence in Keplerian accretion disks. Motivated by recent laboratory experiments, we study the MRI…
Hydrodynamic turbulence in quasi-Keplerian rotating flows
Liang Shi, Bjoern Hof, Markus Rampp +1
We report a direct-numerical-simulation study of Taylor-Couette flow in the quasi-Keplerian regime at shear Reynolds numbers up to . Quasi-Keplerian rotating flo…