A pencil distributed finite difference code for strongly turbulent wall-bounded flows

Poel, Erwin P. van der; Ostilla–Mónico, Rodolfo; Donners, John; Verzicco, Roberto

doi:10.1016/j.compfluid.2015.04.007

Cited by 189 publications

(195 citation statements)

References 50 publications

(63 reference statements)

Supporting

Mentioning

192

Contrasting

Order By: Relevance

“…An advectiondiffusion equation for a scalar field, even when dealing with an active scalar such as the temperature field in thermal convection discussed in Ref. [32], can be discretized in rather naïve ways and still produce somewhat accurate results. But ion-concentration fields have exponential boundary layers (the electrical double layer) which can cause problems with ion conservation if not treated correctly.…”

Section: Methodsmentioning

confidence: 99%

“…More details about the Navier-Stokes solver, validation procedures and performance can be found in Refs. [31,32].…”

Section: Methodsmentioning

confidence: 99%

“…[31,32] for an extended discussion), we Fourier transform the two homogeneous directions and solve the resulting tridiagonal matrix using the Thomas algorithm in the wall-normal direction. The only difference is that the pressure field has a Neumann boundary conditions (∂ n p = 0) at the wall, while the potential perturbation has a Dirichlet boundary condition (φ = 0) at the wall.…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Controlling turbulent drag across electrolytes using electric fields

Ostilla–Mónico

Lee

2017

Faraday Discuss.

Self Cite

View full text Add to dashboard Cite

Reversible in operando control of friction is an unsolved challenge crucial to industrial tribology. Recent studies show that at low sliding velocities, this control can be achieved by applying an electric field across electrolyte lubricants. However, the phenomenology at high sliding velocities is yet unknown. In this paper, we investigate the hydrodynamic friction across electrolytes under shear beyond the transition to turbulence. We develop a novel, highly parallelised, numerical method for solving the coupled Navier-Stokes Poisson-Nernest-Planck equation. Our results show that turbulent drag cannot be controlled across dilute electrolyte using static electric fields alone. The limitations of the Poisson-Nernst-Planck formalism hints at ways in which turbulent drag could be controlled using electric fields.

show abstract

Section: Methodsmentioning

confidence: 99%

“…More details about the Navier-Stokes solver, validation procedures and performance can be found in Refs. [31,32].…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Controlling turbulent drag across electrolytes using electric fields

Ostilla–Mónico

Lee

2017

Faraday Discuss.

Self Cite

View full text Add to dashboard Cite

show abstract

“…An immersed boundary method [32] is implemented to simulate the ratchet surfaces. The code has been extensively validated and used [30,31,33]. Adequate resolutions [34] are ensured for all simulations so that the results are grid independent.…”

mentioning

confidence: 99%

“…In addition to the experiments, three-dimensional direct numberical simulations (DNS) of the Boussinesq equations are performed by using the in-house AFiD code [30,31]. An immersed boundary method [32] is implemented to simulate the ratchet surfaces.…”

mentioning

confidence: 99%

Controlling Heat Transport and Flow Structures in Thermal Turbulence Using Ratchet Surfaces

et al. 2018

Self Cite

View full text Add to dashboard Cite

In this combined experimental and numerical study on thermally driven turbulence in a rectangular cell, the global heat transport and the coherent flow structures are controlled with an asymmetric ratchet-like roughness on the top and bottom plates. We show that, by means of symmetry breaking due to the presence of the ratchet structures on the conducting plates, the orientation of the Large Scale Circulation Roll (LSCR) can be locked to a preferred direction even when the cell is perfectly leveled out. By introducing a small tilt to the system, we show that the LSCR orientation can be tuned and controlled. The two different orientations of LSCR give two quite different heat transport efficiencies, indicating that heat transport is sensitive to the LSCR direction over the asymmetric roughness structure. Through a quantitative analysis of the dynamics of thermal plume emissions and the orientation of the LSCR over the asymmetric structure, we provide a physical explanation for these findings. The current work has important implications for passive and active flow control in engineering, bio-fluid dynamics, and geophysical flows.Turbulent convective flows over rough surfaces are ubiquitous in engineering and geophysical flows. Examples include convective flows in the atmosphere and in oceans, where the ground, sea-bed and ocean floor are generally not smooth. As the ability to enhance convective heat transfer is crucial in many industrial applications, numerous strategies have been proposed to efficiently enhance it. Among several approaches, introducing wall roughness is an effective way to do so. Indeed, the study of surface roughness effects in wall-bounded turbulent flows has been an area of intense research (see e.g. some recent work [1][2][3][4][5][6][7][8], the reviews [9,10], and the textbooks [11,12]). Similarly, several studies have been conducted on turbulent thermal convection over rough plates [13][14][15][16][17][18][19][20]. The vast majority of these studies with rough walls adopt some ordered and symmetrical structures, such as pyramids, squares, rectangles etc. However, the rough surfaces in engineering applications and in nature are in general not symmetric, resulting in complex interactions between the flow and the asymmetric roughness elements. Examples are wind blowing over a landscape with asymmetric slopes and ocean flows over an asymmetric sea-bed, etc. Other examples include marine animals which can actively change the asymmetric roughness for maneuverability.In this work, we aim to study the influences of ratchetlike wall structures on the flow organization and heat transfer in fully developed convective thermal turbulence. Indeed, building on the classical Feynman-Smoluchowski ratchet, in various contexts researchers have proposed ratchet-type mechanisms and devices that operate outside of thermal equilibrium [21]. Examples include the so-called 'capillary-ratchet' in zoology [22], a rotational ratchet in a granular gas [23], self-propelled Leidenfrost droplets and solids on ratchet sur...

show abstract