Skip to main content

Fluid Simulation and Modeling

ABOUT OUR RESEARCH

The motion of liquids and gases plays a key role in numerous natural phenomena and determines the viability and efficiency of many processes in aerospace, mechanical, chemical and biomedical engineering. In general, fluids can flow in a smooth and orderly manner, such as blood does in small capillaries, or fluctuate erratically as seen in the swirls behind an airplane wing. Hence making quantitative predictions of fluid flows is essential relevance in engineering and also for whether or climate predictions. Our group develops and applies methods to quantify and predict fluid motion by leveraging theoretical, numerical and experimental techniques. Examples of our current interest are energy transfers through gravity waves in the atmosphere, the transition to turbulence in wind-turbines and in the human cardiovascular system, the turbulent mixing of liquids in reactors and the dynamics of bubbles in water electrolysis.

Droplet breakup

Drop breakup in turbulent fluids is a key mechanism in environmental and engineering processes, but remains poorly understood. We developed a novel computer code, which for the first time enables the fast generation of thousands of fully resolved simulations. Leveraging this code, we showed that drop breakup is a memoryless process whose rate depends only on the ratio of inertial to surface-tension forces. A simple model based on the computed breakup rates accurately predicts experimental measurements and demonstrates that dilute emulsions evolve through a continuous fragmentation process with exponentially increasing time scales. 

A. Vela-Martín & M. Avila, Science Advances, 8:abp9561 (2022)

Our fields of research

  • Flow instabilities
  • Turbulence
  • Fluid-structure interaction
  • Mixing
  • Bubbly and droplet-laden flows 
  • Optimization of fluid transport

CONTACT

Transition to turbulence in pulsatile pipe flow

Pulsatile flow in a straight pipe is a model system for unsteady internal flows in industrial engineering and physiology. In some parameter regimes, the laminar flow is susceptible to helical perturbations, whose transient energy growth scales exponentially with the Reynolds number (Re). We link the transient growth of these perturbations to the instantaneous linear instability of the laminar flow.

We exploit this link to study the effect of the waveform on turbulence transition by performing linear stability and transient growth analyses of flows driven with different waveforms. We find a higher-energy growth in flows driven with longer low-velocity phases as well as with steeper deceleration and acceleration phases.

Funded by the DFG through project "Instabilities, bifurcations and migration in pulsating flow"

Turbulent mixing

The efficient mixing of fluids is key in many applications, such as chemical reactions and nanoparticle
precipitation. Detailed experimental measurements of the mixing dynamics are however difficult to
obtain, and so predictive numerical tools are helpful in designing and optimizing many processes. Turbulent mixing at small scales is poorly understood, which adds to the intrinsic difficulties of modeling turbulence. 

As a result, quantitative model predictions of mixing-sensitive, continuous reactions in chemical engineering remain elusive. Hence water-water mixtures in simple geometries such as T-mixers have been intensively investigated, but little is known about the dynamics of more complex mixtures, especially in the turbulent regime. We exploit numerical and experimntal techniques to study the mixing process in a T-shaped mixer. 

Funded by the DFG through project "Formation of small-scale mixing processes in a T-mixer"

Gravity wave genesis

Understanding and representing the effects of gravity waves (GWs) in weather and climate models, remains an order-of-one challenge, with important implications for the representation of energy and momentum transport in the atmosphere. We aim to determine the dependence of GW break-up, dissipation and secondary emission on the source and environment to pave the way for accurate parametrisations of these processes.

The novelty of this subproject is to study the complete route from GW instability to break-up, dissipation and secondary emission by combining direct numerical simulation (DNS) and new advances in flow stability analysis.

Funded by DFG through project "Generation, decay and dissipation of gravity waves"

Boundary layer in wind turbine blades

During the operation under the harsh conditions of the atmospheric boundary layer, the rotor blades of wind turbines are directly exposed to mechanical influences such as raindrops, sand grains or insects. As a result, the leading edge of the rotor blades suffers from erosion damages and contamination, which lead to aerodynamic performance losses of up to 25 % and premature fatigue failures. For this reason, a condition monitoring of rotor blades with an early detection and characterisation of initial surface defects on wind turbines in operation is needed.

Our aim is to make use of the effect of a local surface defect (as a flow disturbance element) on the boundary layer flow as a measuring principle. By means of thermographic flow visualisation, an indirect, non-invasive measurement of the defect properties type (additive/subtractive), size, shape (aspect ratio) and position is reached. Thus, the characterization of incipient surface defects, which cannot be measured with a direct imaging approach due to the large measuring distance to the ground, will become possible.

This project is in collaboration with Prof. Andreas Fischer (University of Bremen).

Funded by DFG through project "Indirect assessment of local surface defects on wind turbine rotor blades"

 

Bubble detachment in electrolysis

From boiling water to hydrogen production in electrolysers, bubbles form, grow, and eventually detach from surfaces. But how big are they when they break away? Our computer simulations aim to answer this question, which is especially important for future space missions. On Mars, where gravity is only 38% of Earth's, bubbles experience weaker buoyant forces, potentially affecting everything from fuel production to oxygen supplies. This research, funded by the Humans on Mars initiative, helps us understand how bubbles behave in low gravity—an essential step for designing efficient systems for space exploration.

This project is in collaboration with Prof. Lutz Mädler, Prof. Fabio La Mantia & Prof. Katharina Brinkert (University of Bremen).

Funded by "Humans on Mars Initiative" project. 

Nonlinear optimal disturbances in turbulent channel flow

From aircraft moving through the air to fluids being pumped through pipes and even forecasting the weather, turbulence plays a crucial role in many technical and natural flow systems. Despite this, fundamental aspects about it are still poorly understood, which means that it is often also the barrier to more accurate predictions in these systems. In this project, we study the mechanisms through which turbulence is sustained in simple shear flows, in particular channel flow. We make use of recent progress in computing hardware, especially GPUs, to study such systems with methods whose application would not have been computationally feasible just a few years ago. 

Using direct numerical simulation and nonlinear adjoint optimisation, disturbances capable of optimally amplifying disturbance energy are calculated. It is hypothesised that these disturbances and their time evolution isolate the most important mechanisms for transferring energy from the base flow to the turbulent fluctuations, and thus, that studying them can help answer the fundamental open question of how turbulence is sustained in shear flows.

This project is in collaboration with Prof. Rich Kerswell (University of Cambridge).

{f:if(condition: address.contentObjectData.sys_language_uid == 2, then: 'Ein Bild von {address.firstName} {address.lastName}', else: 'Image of {address.firstName} {address.lastName}')}

Dr. Daniel Morón Montesdeoca

Researcher

+49 421 218 - 57842

daniel.moron
{f:if(condition: address.contentObjectData.sys_language_uid == 2, then: 'Ein Bild von {address.firstName} {address.lastName}', else: 'Image of {address.firstName} {address.lastName}')}

Patrick Keuchel

Researcher

+49 421 218 - 57841

patrick.keuchel
{f:if(condition: address.contentObjectData.sys_language_uid == 2, then: 'Ein Bild von {address.firstName} {address.lastName}', else: 'Image of {address.firstName} {address.lastName}')}

Mohammad Mehdi Zamani Asl

Researcher

+49 421 218 - 57838

mehdi.zamani
{f:if(condition: address.contentObjectData.sys_language_uid == 2, then: 'Ein Bild von {address.firstName} {address.lastName}', else: 'Image of {address.firstName} {address.lastName}')}

Dr. Dario Klingenberg

Researcher


dario.klingenberg
{f:if(condition: address.contentObjectData.sys_language_uid == 2, then: 'Ein Bild von {address.firstName} {address.lastName}', else: 'Image of {address.firstName} {address.lastName}')}

Dr. Ianto Cannon

Researcher

+49 421 218 - 57962

ianto.cannon
{f:if(condition: address.contentObjectData.sys_language_uid == 2, then: 'Ein Bild von {address.firstName} {address.lastName}', else: 'Image of {address.firstName} {address.lastName}')}

Felix Kranz

Researcher

+49 421 218 - 57851

felix.kranz
{f:if(condition: address.contentObjectData.sys_language_uid == 2, then: 'Ein Bild von {address.firstName} {address.lastName}', else: 'Image of {address.firstName} {address.lastName}')}

Marika Federer

Researcher

+49 421 218 - 57909

marika.federer
{f:if(condition: address.contentObjectData.sys_language_uid == 2, then: '{settings.defaultEmployeePictureAltDE.value}', else: '{settings.defaultEmployeePictureAltEN.value}')}

Anna Becker

Researcher

+49 421 218 - 57860

anna.becker
{f:if(condition: address.contentObjectData.sys_language_uid == 2, then: '{settings.defaultEmployeePictureAltDE.value}', else: '{settings.defaultEmployeePictureAltEN.value}')}

Marcel Bernauer

Researcher

+49 421 218 - 57923

marcel.bernauer
{f:if(condition: address.contentObjectData.sys_language_uid == 2, then: '{settings.defaultEmployeePictureAltDE.value}', else: '{settings.defaultEmployeePictureAltEN.value}')}

Holger Faust

Engineering Staff

+49 421 218 - 57867

holger.faust
{f:if(condition: address.contentObjectData.sys_language_uid == 2, then: 'Ein Bild von {address.firstName} {address.lastName}', else: 'Image of {address.firstName} {address.lastName}')}

Katja Krömer

Engineering Staff

+49 421 218 - 57861

katja.kroemer
{f:if(condition: address.contentObjectData.sys_language_uid == 2, then: '{settings.defaultEmployeePictureAltDE.value}', else: '{settings.defaultEmployeePictureAltEN.value}')}

Dr. Manojit Ghosh

Visiting researcher


manojit.ghosh

The list below shows the latest 25 publications of this research group. For the complete, searchable list of ZARM publications, please click more

2025

Morón, Daniel; Vela-Martín, Alberto; Avila, Marc
Predictability of decay events in transitional wall-bounded flows
, Journal of Physics: Conference SeriesVolume2753, Page 012009
Publisher: IOP Publishing
2025

2024

Simonini, Alessia; Dreyer, Michael; Urbano, Annafederica; Sanfedino, Francesco; Himeno, Takehiro; Behruzi, Philipp; Avila, Marc; Pinho, Jorge; Peveroni, Laura; Gouriet, Jean-Baptiste
Cryogenic propellant management in space: open challenges and perspectives
npj Microgravity, 10 (1) :34
2024
ISSN: 2373-8065

Vela-Martín, Alberto; Avila, Marc
Large-scale patterns set the predictability limit of extreme events in Kolmogorov flow
Journal of Fluid Mechanics, 986 :A2
2024
ISSN: 0022-1120

Ramalho, Tiago P; Baumgartner, Vincent; Kunst, Nils; Rodrigues, David; Bohuon, Emma; Leroy, Basile; Pillot, Guillaume; Heinicke, Christiane; Kerzenmacher, Sven; Avila, Marc
Resource-efficiency of cyanobacterium production on Mars: Assessment and paths forward
Algal Research, 84 :103801
2024
ISSN: 2211-9264

Morón, Daniel; Avila, Marc
Turbulent puffs in transitional pulsatile pipe flow at moderate pulsation amplitudes
Physical Review Fluids, 9 (2) :024601
2024

2023

Schikarski, Tobias; Trzenschiok, Holger; Avila, Marc; Peukert, Wolfgang
Impact of solvent properties on the precipitation of active pharmaceutical ingredients
Powder Technology, 415 :118032
2023
ISSN: 0032-5910

Feldmann, Daniel; Borrero-Echeverry, Daniel; Burin, Michael J; Avila, Kerstin; Avila, Marc
Routes to turbulence in Taylor–Couette flow
Philosophical Transactions of the Royal Society A, 381 (2246) :20220114
2023
ISSN: 1364-503X

2022

Endres, Stefan Christian; Avila, Marc; Mädler, Lutz
A discrete differential geometric formulation of multiphase surface interfaces for scalable multiphysics equilibrium simulations
Chemical Engineering Science, 257 :117681
2022
ISSN: 0009-2509

Morón, Daniel; Feldmann, Daniel; Avila, Marc
Effect of waveform on turbulence transition in pulsatile pipe flow
Journal of Fluid Mechanics, 948 :A20
2022
ISSN: 0022-1120

Schikarski, Tobias; Avila, Marc; Peukert, Wolfgang
En route towards a comprehensive dimensionless representation of precipitation processes
Chemical Engineering Journal, 428 :131984
2022
ISSN: 1385-8947

Li, Huixin; Fischer, Andreas; Avila, Marc; Xu, Duo
Measurement error of tracer-based velocimetry in single-phase turbulent flows with inhomogeneous refractive indices
Experimental Thermal and Fluid Science, 136 :110681
2022
ISSN: 0894-1777

Vela-Martín, Alberto; Avila, Marc
Memoryless drop breakup in turbulence
Science Advances, 8 (50) :eabp9561
2022
ISSN: 2375-2548

Meyer, Florian; Eigenbrod, Christian; Wagner, Volker; Paa, Wolfgang; Hermanson, James C; Ando, Shion; Avila, Marc
Oxygen droplet combustion in hydrogen under microgravity conditions
Combustion and Flame, 241 :112081
2022
ISSN: 0010-2180

Schikarski, Tobias; Avila, Marc; Trzenschiok, Holger; Güldenpfennig, Andreas; Peukert, Wolfgang
Quantitative modeling of precipitation processes
Chemical Engineering Journal, 444 :136195
2022
ISSN: 1385-8947

Vela-Martín, Alberto
Subgrid-scale models of isotropic turbulence need not produce energy backscatter
Journal of Fluid Mechanics, 937 :A14
2022
ISSN: 0022-1120

Vela-Martín, Alberto
The energy cascade as the origin of intense events in small-scale turbulence
Journal of Fluid Mechanics, 937 :A13
2022
ISSN: 0022-1120

2021

Verseux, Cyprien; Heinicke, Christiane; Ramalho, Tiago P; Determann, Jonathan; Duckhorn, Malte; Smagin, Michael; Avila, Marc
A low-pressure, N2/CO2 atmosphere is suitable for Cyanobacterium-based life-support systems on Mars
Frontiers in Microbiology, 12 :67
2021
ISSN: 1664-302X

Gasow, Stefan; Kuznetsov, Andrey V; Avila, Marc; Jin, Yan
A macroscopic two-length-scale model for natural convection in porous media driven by a species-concentration gradient
Journal of Fluid Mechanics, 926 :A8
2021
ISSN: 0022-1120

Li, Huixin; Avila, Marc; Xu, Duo
A single-camera synthetic Schlieren method for the measurement of free liquid surfaces
Experiments in Fluids, 62 :1-15
2021
ISSN: 0723-4864

Vela-Martín, Alberto; Avila, Marc
Deformation of drops by outer eddies in turbulence
Journal of Fluid Mechanics, 929 :A38
2021
ISSN: 0022-1120

Plana, Carlos; Song, Baofang; Avila, Marc
Direct numerical simulation of two-phase pipe flow: influence of the domain length on the flow regime
International Journal of Multiphase Flow, 144 :103786
2021
ISSN: 0301-9322

Tielke, J; Maas, M; Castillo, M; Rezwan, K; Avila, M
Statistical analysis of thermal conductivity experimentally measured in water-based nanofluids
Proceedings of the Royal Society A, 477 (2250) :20210222
2021
ISSN: 1364-5021

Vela-Martín, Alberto
The synchronisation of intense vorticity in isotropic turbulence
Journal of Fluid Mechanics, 913 :R8
2021
ISSN: 0022-1120

2020

Gasow, Stefan; Lin, Zhe; Zhang, Hao Chun; Kuznetsov, Andrey V; Avila, Marc; Jin, Yan
Effects of pore scale on the macroscopic properties of natural convection in porous media
Journal of Fluid Mechanics, 891
2020
ISSN: 0022-1120

Xu, Duo; Song, Baofang; Avila, Marc
Non-modal transient growth of disturbances in pulsatile and oscillatory pipe flow
arXiv preprint arXiv:2008.04616
2020