Two‐dimensional prediction of time dependent, turbulent flow around a square cylinder confined in a channel

Raisee, Mehrdad; Jafari, Azadeh; Babaei, Hashem; Iacovides, Hector

doi:10.1002/fld.2065

Cited by 9 publications

(3 citation statements)

References 25 publications

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“…In the second solution stage, for obtaining an iteration equation of the vorticity, it can be followed the same way with the stream function. Consequently, to compute stream function and vorticity values with fourth-order accuracy in any grid points and with iterative manner, can be used iteration equation (17) and (18), respectively.…”

Section: Governing Equations Of Fourth-order Compact Formulationmentioning

confidence: 99%

Numerical Analysis of Flow Around Bluff Bodies with 4th and 2nd order compact formulations

Aslan

Inan

Kandemir

et al. 2018

Sakarya University Journal of Science

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In the present study, fourth-order compact formulation has been improved for Navier-Stokes (N-S) equations, which is expressed for two-dimensional, steady, incompressible flow problems. N-S equation system has been expressed with Stream Function-Vorticity Approach using Finite Difference Method (FDM) from the numerical methods. In order to test the functionality and applicability of the improved numerical formulation, a sample for submerged bluff bodies, flow problem around cylinder with square cross-section was chosen as a benchmark problem. As a result of applying improved numerical formulation with Gauss-Seidel Relaxation Method was used for this benchmark problem. The benchmark problem was also solved with second-order accuracy and obtained numerical results were compared with fourth-order accuracy numerical results. With the same Reynolds Number and the same free-stream velocity values, fourth-order numerical results are more convergent than second-order numerical results. Furthermore, in the flow field for considered benchmark problem, separation bubble length that consisted in the wake region is increased proportionally depending on the alteration of the Reynolds Number values.

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Section: Governing Equations Of Fourth-order Compact Formulationmentioning

confidence: 99%

Numerical Analysis of Flow Around Bluff Bodies with 4th and 2nd order compact formulations

Aslan

Inan

Kandemir

et al. 2018

Sakarya University Journal of Science

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“…Açık kanal akımlarında SAD çözümü ile doğru hız profilleri hesaplamak için türbülans yapısının tam olarak modellenmesi gerekir. Bu anlamda birçok çalışma yapılmış olmakla birlikte ( [12], [13], [14], [15], [16]) SAD çözümleri için henüz genel kabul görmüş bir derinlik integralli türbülans modeli yoktur. Yapılan bazı çalışmalarda ise bir model tanımlamak yerine ampirik ifadelerle deneysel verilere uyum sağlanması denenmiştir [17].…”

Section: Bileşik Kesitli Prizmatik Kanalda üNiform Akımunclassified

Sığ Akım Denklemlerinin Hidrolikte Kullanılması Üzerine Değerlendirmeler

Işcen¹,

Öktem²,

Yılmaz³

et al. 2017

Teknik Dergi

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ÖZSığ akım denklemlerinin geniş alanlara yayılan taşkınları hesaplamada başarılı olduğu bilinmekte ve bu denklemler taşkın analizleri için yaygın olarak kullanılmaktadır. Kentsel alanlardaki yapılar arasında ilerleyen taşkınlar ve köprü gibi hidrolik yapılar etrafındaki akımlar sığ akım sınırlamalarını tam olarak sağlamamakta ve daha çok 3-Boyutlu (3B) akım özelliği taşımaktadır. Ancak, hızlı sayısal çözüm kolaylığı bakımından sığ-akım denklemleri bu tür 3B akımlar için de kullanılabilmekte ve yararlı çıktılar elde edilebilmektedir.Bu çalışmada, sığ akım denklemleri, 3B özellikleri öne çıkan akımlara uygulanarak sonuçları değerlendirilmiştir. Su derinliği ve yatay düzlemde hız dağılımımın yeterli ayrıntıda hesaplanabildiği, sel rejiminde su yüzünde oluşan şok dalgalarının ayrıntılı olarak tanımlanabildiği gözlenmiştir. Ancak, birden fazla 3B engel etrafından geçen akımlarda su derinliği hesaplamadaki hataların eklenerek arttığı belirlenmiştir. Sınır tabaka özelliklerinin öne çıktığı üniform akım durumunda uygun bir türbülans modeli kullanılması halinde, hız ve yatak kesme gerilmeleri dağılımlarının da başarıyla hesaplanabildiği gösterilmiştir.Anahtar Kelimeler: Sel, taşkın, sığ akım denklemleri, şok yakalayıcı çözümler, Riemann çözücüler.

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“…The nonlinear low-Re k - ε model gave excellent heat transfer predictions both within the recirculation bubble and in the developing region. The capabilities of the nonlinear low-Re k - ε model in the prediction of unsteady turbulent flows were further investigated in Raisee et al (2010). The numerical results demonstrated that the nonlinear k - ε model is able to give accurate results for the time-averaged velocity and turbulence quantities.…”

Section: Introductionmentioning

confidence: 99%

Computation of flow and heat transfer through channels with periodic dimple/protrusion walls using low-Reynolds number turbulence models

Fazli

Raisee

2019

HFF

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Purpose This paper aims to predict turbulent flow and heat transfer through different channels with periodic dimple/protrusion walls. More specifically, the performance of various low-Re k-ε turbulence models in prediction of local heat transfer coefficient is evaluated. Design/methodology/approach Three low-Re number k-ε turbulence models (the zonal k-ε, the linear k-ε and the nonlinear k-ε) are used. Computations are performed for three geometries, namely, a channel with a single dimpled wall, a channel with double dimpled walls and a channel with a single dimple/protrusion wall. The predictions are obtained using an in house finite volume code. Findings The numerical predictions indicate that the nonlinear k-ε model predicts a larger recirculation bubble inside the dimple with stronger impingement and upwash flow than the zonal and linear k-ε models. The heat transfer results show that the zonal k-ε model returns weak thermal predictions in all test cases in comparison to other turbulence models. Use of the linear k-ε model leads to improvement in heat transfer predictions inside the dimples and their back rim. However, the most accurate thermal predictions are obtained via the nonlinear k-ε model. As expected, the replacement of the algebraic length-scale correction term with the differential version improves the heat transfer predictions of both linear and nonlinear k-ε models. Originality/value The most reliable turbulence model of the current study (i.e. nonlinear k-ε model) may be used for design and optimization of various thermal systems using dimples for heat transfer enhancement (e.g. heat exchangers and internal cooling system of gas turbine blades).

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Two‐dimensional prediction of time dependent, turbulent flow around a square cylinder confined in a channel

Cited by 9 publications

References 25 publications

Numerical Analysis of Flow Around Bluff Bodies with 4th and 2nd order compact formulations

Numerical Analysis of Flow Around Bluff Bodies with 4th and 2nd order compact formulations

Sığ Akım Denklemlerinin Hidrolikte Kullanılması Üzerine Değerlendirmeler

Computation of flow and heat transfer through channels with periodic dimple/protrusion walls using low-Reynolds number turbulence models

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