Computational Fluid Mechanics Lab

Welcome to the webpage of the research group of O. Flores and M. García-Villalba.

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Turbulent flows are present in many Aerospace Engineering applications. They are also very common in other engineering areas, ranging from Astrophysical and Geophysical problems to the design of high-tech swimsuits for the Olympic Games. In the Computational Fluid Mechanics Lab we analyze turbulent flows using Direct Numerical Simulation (DNS) and Large Eddy Simulations (LES) that run in massive parallel supercomputers. This webpage contains a brief description of some of our projects.
A brief description of the research projects of our group can be found below, followed by our publications and a list of our collaborators.

At the present time, 4 PhD students (A. Almagro, A. Antoranz, G. Arranz and A. Gonzalo) and 1 postdoc (M. Moriche) are working in this group.
our staff !!
June 2015

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Research Projects




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Unsteady Aerodynamics of flapping wings. Inspired by the maneuverability of birds and insects, our aim is to develop numerical tools that allow the design of flight control strategies for flapping Micro Air Vehicles. Our research is based on numerical simulations performed with TUCAN, an in-house DNS solver for the Navier-Stokes equations that uses an Immersed Boundary method. We are interested in analyzing the flow around flapping wings and the stability of the vortices, as well as the 2-way coupling between the aerodynamic forces and the dynamic response of the vehicle.
This research is funded by the Spanish Ministry of Economy and Competitivity, thru several consecutive grants (TRA 2012-37714, TRA 2013-, TRA 2016-). M.M, G.A and A.G actively work in this problem. We also collaborates with the Universidad de Malaga and the Karsrhue Institute of Technology.




turbulent mixing layers:-( Variable density mixing layers: non-reactive and reactive. This research is enclosed within the framework of a Consolider-Ingenio 2010 project, SCORE (contract # CSD2010-00011), that aims at the development of advanced and sustainable combustion systems. In colaboration with the Fluid Mechanics Department of the UC3M, we aim at analyzing the effect that the Lewis number has on the flame temperature of turbulent diffusion flames in a canonical configuration: a turbulent mixing layer. DNS are performed using a massively parallel solver of the Navier-Stokes equations in the low-Mach number approximation. As a stepping stone in the project, we have also simulated and analized non-reactive turbulent mixing layers between streams of different densities.
A.A is working on this project as part of his PhD studies.




turbulence collapse in a stably stratified channel:-( Stratified flows Stably-stratified turbulent wall flows are receiving a growing interest due to their relevance in environmental engineering and geophysical applications. The atmospheric boundary layer is typically stably stratified at night while oceanic flows are almost always stably stratified. Topics of current research in these flows are, among others, the quantification of mixing, the dynamics of strongly stratified turbulence and the structure and the modeling of stable boundary layers. UW and UCSD are involved in this research effort, which has been funded by ARO (W911NF-08-1-0155).



solid particles in a turbulent channel:-( Multiphase flows Fluid flow with suspended solid particles is encountered in a multitude of natural and industrial systems. Examples include the motion of sediment particles in rivers, fluidized beds and blood flow. Despite the great technological importance of these systems our understanding of the dynamics of fluid-particle interaction is still incomplete at the present date. Recently, it has become possible to simulate the motion of a considerable number of finite-size particles including an accurate description of the surrounding flow field on the particle scale. This project is a cooperation with KIT.



wall-bounded turbulence example:-( Wall bounded turbulent flows Many turbulent flows of engineering interest are bounded by solid surfaces (walls), which are responsible for the generation of friction drag, one of the main concerns of Aerospace industry. Also, most engineering applications attempt to control turbulent flows using actuators at these surfaces. The success of these applications depend on our ability to predict the interaction between walls and turbulent eddies. The natural roughness of the surface, or the deposition of debris, complicates these interactions. In the CFD Lab., we use DNS of simple wall-bounded flows to improve our understanding of wall-bounded turbulent flows. This line of research benefits from collaborations with UPM, UT and UW.



flow separation in a 3D hill:-( Flow separation The separation of a turbulent boundary layer from a gently curving surface is a process of primary concern in numerous engineering components and applications. A few examples are highly loaded aircraft wings, fuselages at high incidence or low-pressure turbine blades. In all these cases presence or absence of flow separation can have a decisive influence on the ability of the device to perform effectively and safely. DNS and LES can be used to understand and predict this behaviors.




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Publications

  1. A numerical study of a variable-density low-speed turbulent mixing layer.
    Almagro, García-Villalba & Flores. J. Fluid Mech., accepted (2017) [link]
  2. On the aerodynamic forces on heaving and pitching airfoils at low Reynolds number
    Moriche, Flores & García-Villalba. J. Fluid Mech., accepted (2017) [link]
  3. On the dynamics of turbulence near a free-surface
    Flores, Riley & Horner-Devine. J. Fluid Mech., 821, 248-265 (2017) [link]
  4. Modeling and dynamics of a two-line kite
    Sánchez-Arriaga, García-Villalba & Schmehl. Appl. Math. Model., 47C, 473-486, (2017) [link]
  5. Influence of the secondary motions on pollutant mixing in a meandering open channel flow.
    Moncho-Esteve, Folke, García-Villalba & Palau-Salvador. Environ. Fluid Mech., 17, 695-714 (2017) [link]
  6. Three-dimensional instabilities in the wake of a flapping wing at low Reynolds number
    Moriche, Flores & García-Villalba. Int. J. Heat Fluid Flow, 62, 44-55 (2016) [link]
  7. Heat transfer and thermal stresses in a circular tube with a non-uniform heat flux.
    Marugán-Cruz, O. Flores, D. Santana & García-Villalba. Int. J. Heat Mass TRansfer, 96, 256-266 (2016) [link]
  8. Hairpin vortices in turbulent boundary layers
    Etiel-Amor, Orlu, Schlatter & Flores Phys. Fluids, 27, 2, 10.1063/1.4907783 (2015) [link]
  9. Numerical simulation of heat transfer in a pipe with non-homogeneous thermal boundary conditions
    Antoranz, Gonzalo, Flores & García-Villalba. Int. J. Heat and Fluid Flow, 55, 45-51 (2015) [link]
  10. Forced Convection Heat Transfer from a Finite-Height Cylinder
    García-Villalba, Palau-Salvador & Rodi. Flow, Turb. and Comb., 93, 1, 171-187(2014) [link]
  11. Experimental and large eddy simulation study of the flow developed by a sequence of lateral obstacles
    Brevis, García-Villalba & Nińo. Env. Fluid Mech., 14, 4, 873-893 (2014) [link]
  12. Spatial and temporal scales of force and torque acting on wall-mounted spherical particles in open channel flow
    Chan-Braun, García-Villalba & Uhlmann. Phys. Fluids, 25, 075103 (2013) [link]
  13. DNS of vertical plane channel flow with finite-size particles: Voronoi analysis, acceleration statistics and particle-conditioned averaging
    García-Villalba, Kidanemariam & Uhlmann. Int. J. Multiphase Flow, (2012) [link]
  14. The three-dimensional structure of momentum transfer in turbulent channels
    Lozano-Durán, Flores & Jiménez. J Fluid Mech, doi:10.1017/jfm.2011.524 (2012) [link] [pdf]
  15. Force and torque acting on particles in a transitionally rough open channel flow
    Chan-Braun, García-Villalba & Uhlmann. J Fluid Mech, 684, pp 441-474, (2011) [link]
  16. Turbulence modification by stable stratification in channel flow
    García-Villalba & del Álamo. Phys Fluids, 23, 045104 (2011). [link]
  17. Analysis of turbulence collapse in the stable stratified surface layer using Direct Numerical Simulation Flores & Riley. Boundary-Layer Meteorol, 139 pp 241-259 (2011). [link] [pdf]
  18. Hierarchy of minimal flow units in the logarithmic layer
    Flores & Jiménez. Phys Fluids, 22 (7) pp 071704 (2010). [link] [pdf]
  19. Large eddy simulation of separated flow over a three-dimensional axisymmetric hill
    García-Villalba, Li, Rodi & Leschziner. J Fluid Mech, 627, 55-96 (2009). [link]
  20. Vorticity organization in the outer layer of turbulent channels with disturbed walls
    Flores, del Álamo & Jiménez. J Fluid Mech, 591 pp 145-154 (2007). [link] [pdf]
  21. Effect of wall-boundary disturbances on turbulent channel flows
    Flores & Jiménez. J Fluid Mech, 566 pp 357-376 (2006). [link] [pdf]
  22. Identification and analysis of coherent structures in the near field of a turbulent unconfined annular swirling jet using large eddy simulation
    García-Villalba, Fröhlich & Rodi. Phys Fluids, 18, 055103 (2006). [link]
  23. The large scale dynamics of near-wall turbulence
    Jiménez, del Álamo & Flores. J Fluid Mech, 505 pp 179-199 (2004). [link] [pdf]




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Collaborators

  1. Juan Carlos del Álamo, University of California San Diego.
  2. Wernher Brevis, University of Sheffield.
  3. Jochen Fröhlich, Technical University of Dresden.
  4. Javier Jiménez, Universidad Politécnica de Madrid.
  5. Robert Moser, University of Texas Austin.
  6. Guillermo Palau, Universidad Politécnica de Valencia.
  7. James J Riley, University of Washington.
  8. Wolfgang Rodi, Karlsruhe Institute of Technology.
  9. Markus Uhlmann, Karlsruhe Institute of Technology.
  10. Jan Wissink, Brunel University.