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Journal ArticleDOI

Numerical investigations of radial jet reattachment flows

TL;DR: In this paper, a finite volume computational scheme to solve the Navier-Stokes equations for the laminar flow fields of partially enclosed axial and radial jets impinging on a flat plate has been devised and tested.
Abstract: SUMMARY A finite volume computational scheme to solve the Navier-Stokes equations for the laminar flow fields of partially enclosed axial and radial jets impinging on a flat plate has been devised and tested. This scheme is based on the SIMPLEC technique. However, because of the backflow at the 'outflow' boundary, the SIMPLEC pressure correction technique has to be modified. The need for this modification, necessitated by the convergence failure, showed the 'hidden' pressure boundary condition of SIMPLE-type techniques. Test computations with the present scheme for flows in a channel with a built-in cylinder show that the location of the exit boundary affects very slightly the separated flow behind the cylinder. Computed Squire jet flows compare quite well with the available analytical solution. Finally, impinging radial jets have been computed for different Reynolds numbers. The results show the critical Reynolds number below which a steady solution is obtained and above which periodic and eventually chaotic flows result.
Citations
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Journal ArticleDOI
TL;DR: In this paper, various pressure-based schemes are proposed for transient flows based on well-established SIMPLE and PISO algorithms, and the implicit treatment and the performance of the various schemes are evaluated by using benchmark solutions with a small time step.
Abstract: Various pressure-based schemes are proposed for transient flows based on well-established SIMPLE and PISO algorithms. The schemes are applied to the solution of unsteady laminar flow around a square cylinder and steady laminar flow over a backward-facing step. The implicit treatment and the performance of the various schemes are evaluated by using benchmark solutions with a small time step. Three different second-order-accurate time derivatives based on different time levels are presented. The different time derivatives are applied to the various schemes under consideration. Overall the PISO scheme was found to predict accurate results and was robust. However, for small time step values, alternative schemes can predict accurate results for approximately half the computational cost. The choice of time derivative proved to be very significant in terms of the accuracy and robustness of a scheme. Significantly, the one-sided forward differencing scheme was the most successful used in conjunction with a strongly implicit-based algorithm. However, a greater degree of accuracy was achieved using the standard PISO algorithm with the Crank–Nicolson time derivative. Recommendations for future work are discussed. © 1998 John Wiley & Sons, Ltd.

138 citations

Journal ArticleDOI
TL;DR: In this paper, the flow field due to an impinging jet at a moderately high Reynolds number, emanating from a rectangular slot nozzle has been computed using a large eddy simulation (LES) technique.

107 citations

Journal ArticleDOI
TL;DR: In this article, the effects of Reynolds number and nozzle-to-plate spacing on the flow structure were investigated for a single jet and double jet and the velocity and pressure distributions in the impingement region were obtained over a Reynolds number range of 300-10,000 and a nozzle toplate spacing range of 0.5-4.

72 citations

Journal ArticleDOI
TL;DR: In this paper, the velocity field and heat transfer in rows of rectangular impinging jets have been analyzed from the numerical solution of unsteady Navier-Stokes and energy equations.
Abstract: The velocity field and heat transfer in rows of rectangular impinging jets have been analyzed from the numerical solution of unsteady Navier-Stokes and energy equations. Jets emanating axially and radially from rectangular slot nozzles (feed tubes) have been considered. For the radial jets, the jet exit angle has also been varied. Steady flows have been obtained for Reynolds numbers smaller than a critical value above which periodic flows appear. At a higher Reynolds number than the critical value, the flow becomes unsteady and nonperiodic. For the laminar axial jets, an optimum relative nozzle area for maximum heat transfer, as experimentally observed for turbulent jets, is also obtained. For the radial jets, heat transfer monotonically increases with relative nozzle area. For the densely spaced jets, i.e.,for a large relative nozzle area, average heat transfer for the radial jets can be larger than that for the axial jets. Heat transfer can also be substantially increased by vectoring the radia...

41 citations

References
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Book
01 Jan 1980
TL;DR: In this article, the authors focus on heat and mass transfer, fluid flow, chemical reaction, and other related processes that occur in engineering equipment, the natural environment, and living organisms.
Abstract: This book focuses on heat and mass transfer, fluid flow, chemical reaction, and other related processes that occur in engineering equipment, the natural environment, and living organisms. Using simple algebra and elementary calculus, the author develops numerical methods for predicting these processes mainly based on physical considerations. Through this approach, readers will develop a deeper understanding of the underlying physical aspects of heat transfer and fluid flow as well as improve their ability to analyze and interpret computed results.

21,858 citations

Journal ArticleDOI
TL;DR: In this paper, a new technique is described for the numerical investigation of the time-dependent flow of an incompressible fluid, the boundary of which is partially confined and partially free The full Navier-Stokes equations are written in finite-difference form, and the solution is accomplished by finite-time step advancement.
Abstract: A new technique is described for the numerical investigation of the time‐dependent flow of an incompressible fluid, the boundary of which is partially confined and partially free The full Navier‐Stokes equations are written in finite‐difference form, and the solution is accomplished by finite‐time‐step advancement The primary dependent variables are the pressure and the velocity components Also used is a set of marker particles which move with the fluid The technique is called the marker and cell method Some examples of the application of this method are presented All non‐linear effects are completely included, and the transient aspects can be computed for as much elapsed time as desired

5,841 citations

Journal ArticleDOI
TL;DR: The performances of SIMPLE, SIMPLER, and SIMPLEC are compared for two recirculating flow problems and several modifications to the method are shown which both simplify its implementation and reduce solution costs.
Abstract: Variations of the SIMPLE method of Patankar and Spalding have been widely used over the past decade to obtain numerical solutions to problems involving incompressible flows. The present paper shows several modifications to the method which both simplify its implementation and reduce solution costs. The performances of SIMPLE, SIMPLER, and SIMPLEC (the present method) are compared for two recirculating flow problems. The paper is addressed to readers who already have experience with SIMPLE or its variants.

3,276 citations

Book ChapterDOI
TL;DR: In this article, the authors present a comprehensive survey emphasizing the engineering applications and empirical equations, presented for the prediction of heat and mass transfer coefficients within a large and technologically important range of variables.
Abstract: Publisher Summary Heating or cooling of large surface area products is often carried out in devices consisting of arrays of round or slot nozzles, through which air impinges vertically upon the product surface. This chapter presents a comprehensive survey emphasizing the engineering applications and empirical equations, presented for the prediction of heat and mass transfer coefficients within a large and technologically important range of variables. The local variations of the transfer coefficients are based on the experimental data for single round nozzles (SRN), arrays of round nozzles (ARN), single slot nozzles (SSN), and arrays of slot nozzles (ASN). The variation of local transfer coefficients is graphically represented. It also explores how to apply these equations in heat exchanger and dryer design as well as in optimization. The flow field of impinging flow is diagrammatically represented. External variables influencing heat and mass transfer in impinging flow depends on mass flow rate, kind and state of the gas and on the shape, size, and position of the nozzles relative to each other and to the solid surface. The design of high-performance arrays of nozzles is also discussed.

1,548 citations

ReportDOI
01 Jan 1975
TL;DR: In this article, a finite difference technique is presented for solving the Navier-Stokes equations for an incompressible fluid, based on the Marker-and-Cell method, to facilitate its use by persons with little or no experience in numerical fluid dynamics.
Abstract: : A finite difference technique is presented for solving the Navier-Stokes equations for an incompressible fluid. The technique, based on the Marker-and-Cell method, is simplified to facilitate its use by persons with little or no experience in numerical fluid dynamics. Section I of the report describes the basic algorithm, SOLA, for confined flows; Sec. II describes modifications necessary for free or curved rigid surface boundaries. Each includes a flow chart and a FORTRAN listing. Sample problems show how to incorporate simple modifications into the basic code to adapt it to a variety of problems.

541 citations