Mechanism of drag generation by surface corrugation

Mohammadi, Alireza; Floryan, J. M.

doi:10.1063/1.3675557

Cited by 34 publications

(13 citation statements)

References 26 publications

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“…It is also known that long wavelength longitudinal grooves can lead to drag reduction through changes in the distribution of the bulk flow (Szumbarski, Blonski & Kowalewski 2011, Moradi & Floryan 2013; Mohammadi & Floryan 2013 a , 2014, 2015; Mohammadi, Moradi & Floryan 2015, Chen et al. 2016; DeGroot, Wang & Floryan 2016; Raayai-Ardakani & McKinley 2017; Yadav, Gepner & Szumbarski 2017, 2018). Such grooves can be optimized (Mohammadi & Floryan 2013 b ) with their most effective forms changing with the imposed constraints.…”

Section: Introductionmentioning

confidence: 99%

On the use of transpiration patterns for reduction of pressure losses

Jiao

Floryan

2021

J. Fluid Mech.

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Section: Introductionmentioning

confidence: 99%

On the use of transpiration patterns for reduction of pressure losses

Jiao

Floryan

2021

J. Fluid Mech.

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“…The same corrugations can introduce two forms of pressure drag. 1 The form drag is generated due to the fact that corrugations present an obstacle to the flow. The pressure interaction drag is generated due to a phase difference between the pressure field and the geometry.…”

Section: Introductionmentioning

confidence: 99%

Groove optimization for drag reduction

Mohammadi

Floryan

2013

Physics of Fluids

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Optimal shapes of laminar, drag reducing longitudinal grooves in a pressure driven flow have been determined. It has been shown that such shapes can be characterized using reduced geometry models involving only a few Fourier modes. Two classes of grooves have been studied, i.e., the equal-depth grooves, which have the same height and depth, and the unequal-depth grooves. It has been shown that the optimal shape in the former case can be approximated by a certain universal trapezoid. There exists an optimum depth in the latter case and this depth, combined with the corresponding groove shape, defines the optimal geometry; this shape is well-approximated by a Gaussian function. Drag reduction due to the use of the optimal grooves has been determined. The analysis has been extended to kinematically driven flows. It has been shown that in this case the longitudinal grooves always increase the flow resistance.

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“…The interests driving the research in this field are both applied and fundamental in nature. From the applied perspective, the interest is due in part to the possible applications of such a configuration to engineering devices for enhanced mixing or heat and mass transfer (Nishimura & Kojima 1995;Wang & Vanka 1995;Wang & Chen 2002;Bahaidarah 2007), but also in part to the possibility of modelling a rough channel through a simplified wavy-roughness version (Floryan 2007;Hasan, Saha & Saha 2012;Mohammadi & Floryan 2012). The interest in fundamental aspects of the problem is due to the opportunity provided by this of the channel is assumed and tested against other periodicity conditions for the particular case analysed.…”

Section: Introductionmentioning

confidence: 99%

Global stability of flow in symmetric wavy channels

Rivera-Alvarez

Ordóñez

2013

J. Fluid Mech.

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A two-dimensional global stability analysis is numerically conducted for the basic fully developed steady flow inside symmetric wavy channels. The relative amplitude of channel modulation, defined as ratio of wall modulation amplitude to mean hydraulic diameter, is fixed via the analysis at a large value of 0.15. The relative channel wavelength, defined as the ratio of wall modulation wavelength to mean hydraulic diameter, is varied between 1 and 5. An important feature of the present approach is the detailed consideration of the streamwise conditions imposed on the flow, which allows a tailored restriction of the possible disturbances by modifying the number of channel sections that set the periodicity. Stability of the base flow is determined on the basis of the spectral structure analysis conducted, possible after calculation of the complete eigenvalue spectrum and facilitated by the spectral method employed. Two different destabilization mechanisms have been identified for the geometry studied. For small relative channel wavelengths, with values below approximately 2.7, the flow is destabilized via a Hopf bifurcation produced by a Tollmien-Schlichting wave at Reynolds numbers in the approximated range from 265 to 324. For large relative channel wavelengths, with values above approximately 2.5, a pitchfork bifurcation (or a Hopf bifurcation with very small oscillation frequency), not previously reported in the literature and produced by a symmetric stationary disturbance, is found at Reynolds numbers in the approximated range from 146 to 230.

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Mechanism of drag generation by surface corrugation

Cited by 34 publications

References 26 publications

On the use of transpiration patterns for reduction of pressure losses

On the use of transpiration patterns for reduction of pressure losses

Groove optimization for drag reduction

Global stability of flow in symmetric wavy channels

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