Suppression of three-dimensional flow instabilities in tube bundles

Kevlahan, Nicholas; Wadsley, James

doi:10.1016/j.jfluidstructs.2005.02.010

Cited by 19 publications

(13 citation statements)

References 16 publications

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“…Since its introduction, Brinkman penalization has been applied to a wide range of fluid flow problems and numerical schemes, including spectral methods (Kevlahan and Ghidaglia, 2001), moving boundaries (Kevlahan and Wadsley, 2005;Kolomenskiy and Schneider, 2009), the wave equation (Paccou et al, 2005), the compressible Euler equations (Liu and Vasilyev, 2007), and the shallow water equations (Perret et al, 2003;Reckinger et al, 2012). The shallow water penalization method we propose is a modification of the one proposed by Reckinger et al (2012) to ensure that mass and energy are conserved and that the wave speed is the same in both the solid and fluid parts of the domain.…”

Section: N K-r Kevlahan Et Al: Adaptive Wavelet Simulation Of Glomentioning

confidence: 99%

Adaptive wavelet simulation of global ocean dynamics using a new Brinkman volume penalization

Kevlahan

Dubos²,

Aechtner

2015

Geosci. Model Dev.

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Abstract. In order to easily enforce solid-wall boundary conditions in the presence of complex coastlines, we propose a new mass and energy conserving Brinkman penalization for the rotating shallow water equations. This penalization does not lead to higher wave speeds in the solid region. The error estimates for the penalization are derived analytically and verified numerically for linearized one-dimensional equations. The penalization is implemented in a conservative dynamically adaptive wavelet method for the rotating shallow water equations on the sphere with bathymetry and coastline data from NOAA's ETOPO1 database. This code could form the dynamical core for a future global ocean model. The potential of the dynamically adaptive ocean model is illustrated by using it to simulate the 2004 Indonesian tsunami and wind-driven gyres.

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Section: N K-r Kevlahan Et Al: Adaptive Wavelet Simulation Of Glomentioning

confidence: 99%

Adaptive wavelet simulation of global ocean dynamics using a new Brinkman volume penalization

Kevlahan

Dubos²,

Aechtner

2015

Geosci. Model Dev.

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“…The pseudo-spectral method is computationally efficient and highly accurate for spatial derivatives, while the Krylov method is a stiffly stable explicit method with an adaptive stepsize to maintain the specified error tolerance. The three-dimensional simulations are parallelized as described in Kevlahan & Wadsley (2005).…”

Section: Methodsmentioning

confidence: 99%

Three-dimensional Floquet stability analysis of the wake in cylinder arrays

Kevlahan

2007

J. Fluid Mech.

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Three-dimensional stability of the periodic wake of tightly packed rotated and inline cylinder arrays is investigated for 60 6 Re 6 270. Results are compared with existing numerical and experimental studies for an isolated cylinder. Numerical Floquet analysis shows that the two-dimensional wakes of the rotated and inline arrays with spacing P/D = 1.5 become unstable at Re c = 64 ± 0.5 and Re c = 132 ± 1 respectively. Two-dimensional vortex shedding flow is unlikely in practice for such flows. The dominant spanwise wavelength is λ/D = 0.9±0.1 for the rotated array at Re = 100 and λ/D = 3.0 ± 0.1 for the inline array at Re = 200. Three-dimensional simulations show excellent agreement with the Floquet analysis for the rotated case, and reasonable agreement for the inline case. The instability mechanism appears to be similar to Mode A for an isolated cylinder, although the structure of the three-dimensional vorticity is different due to the spatial periodicity of the flow. Unlike the isolated cylinder, both array flows are unstable as λ → ∞ (like a thin shear layer). This is the first investigation of three-dimensional wake instability in cylinder arrays, a problem of significant practical and theoretical interest.

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“…Reliability of the pseudo-spectral scheme together with the Brinkman penalization technique, as well as the accuracy of the drag force computed from Equation 17have been previously studied and approved for both 2D and 3D simulations at moderate to high Reynolds numbers [37,38]. However, for low Reynolds number flows, we need to verify the accuracy and perform the grid consistency study.…”

Section: Drag Force: Computation and Validationmentioning

confidence: 99%

A Novel Topology Optimization Approach for Flow Power Loss Minimization Across Fin Arrays

Ghasemi¹,

Elham²

2020

Energies

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Fin arrays are widely utilized in many engineering applications, such as heat exchangers and micro-post reactors, for higher level of fluid–solid contacts. However, high fluid pressure loss is reportedly the major drawback of fin arrays and a challenge for pumping supply, particularly at micro-scales. Previous studies also indicate that fin shapes, spacing and alignment play an important role on the overall pressure losses. Therefore, we present a numerical tool to minimize pressure losses, considering the geometrical aspects related to fin arrays. In this regard, a density-based topology optimization approach is developed based on the pseudo-spectral scheme and Brinkman penalization in 2D periodic domains. Discrete sensitives are derived analytically and computed at relatively low cost using a factorization technique. We study different test cases to demonstrate the flexibility, robustness and accuracy of the present tool. In-line and staggered arrays are considered at various Reynolds numbers and fluid–solid volume fractions. The optimal topologies interestingly indicate a pressure loss reduction of nearly 53.6 % compared to circular fins. In passive optimization test examples, the added solid parts reduced pressure loss of a circular fin ( 9 % ) by eliminating the flow separation and filling the wake region.

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Suppression of three-dimensional flow instabilities in tube bundles

Cited by 19 publications

References 16 publications

Adaptive wavelet simulation of global ocean dynamics using a new Brinkman volume penalization

Adaptive wavelet simulation of global ocean dynamics using a new Brinkman volume penalization

Three-dimensional Floquet stability analysis of the wake in cylinder arrays

A Novel Topology Optimization Approach for Flow Power Loss Minimization Across Fin Arrays

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