A relaxation approach to patched-grid calculations with the Euler equations

Rai, Man

doi:10.2514/6.1985-295

Cited by 31 publications

(14 citation statements)

References 6 publications

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“…The freestream Mach number is 1.5. 37. The numerical fluxes were evaluated using the scheme of Chakravarthy and Osher, 12 and flux limiters were used to render the scheme TVD in each spatial dimension as in Ref.…”

Section: Demonstration Euler Calculationmentioning

confidence: 99%

Computational Analysis of Rotor-Stator Interaction in Turbomachinery Using Zonal Techniques

Madavan

Mohan

1990

Applied Computational Aerodynamics

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IntroductionM OST techniques for the numerical prediction of flows in turbomachinery have been based on the approximation that the flow in each stator or rotor row is steady in the respective frames of reference; i.e., the spacing between adjacent stator and rotor rows is assumed to be far enough that there is no interaction between them. An extensive body of numerical results exists in the literature dealing with a wide variety of twoand three-dimensional cascade geometries, both planar and annular, stationary and rotating (see, for example, Refs. 1-5). Such analyses have gained widespread acceptance in the industrial community and are now being routinely used in the design process.In reality, however, flows in turbomachinery are unsteady. The unsteadiness arises from the interaction of the downstream airfoils with the wakes and passage vortices generated upstream, from the motion of the rotors relative to the stators (potential effect), and from vortex shedding at blunt airfoil trailing edges. The unsteady interaction effects impact the aerodynamic, thermal, and structural performance of the airfoils and become increasingly significant as the distance between successive stator and rotor rows is decreased. The problem of rotor-stator interaction is already having an effect on existing designs, where axial gaps between adjacent airfoil rows of one-fourth to one-half of the airfoil chord are common; these effects are bound to be more severe in future designs with higher loading, lower aspect ratios, and reduced overall length. 6 Thus, a need clearly exists for analytical tools that treat the rotor and stator airfoils as a system and provide Downloaded by PURDUE UNIVERSITY on July 23, 2015 | http://arc.aiaa.org |

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Section: Demonstration Euler Calculationmentioning

confidence: 99%

Computational Analysis of Rotor-Stator Interaction in Turbomachinery Using Zonal Techniques

Madavan

Mohan

1990

Applied Computational Aerodynamics

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“…Multi-block structured grid technique makes it pos-sible to run high-order finite difference schemes on each individual block, and the information transmission between neighbouring blocks and the propagation throughout the flow field can be realized by some kinds of interface conditions. Rai [17] used a flux interpolation to construct coupled conditions on mid-node with Beam-Warming and Osher scheme. Lerat and Wu [18] adopted local flux construction to establish conservative and unconditionally stable interface conditions.…”

Section: High-order and High Accurate Cfd Methods For Complex Grid Prmentioning

confidence: 99%

High-Order and High Accurate CFD Methods and Their Applications for Complex Grid Problems

Deng

Mao

et al. 2012

Commun. comput. phys.

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Abstract. The purpose of this article is to summarize our recent progress in high-order and high accurate CFD methods for flow problems with complex grids as well as to discuss the engineering prospects in using these methods. Despite the rapid development of high-order algorithms in CFD, the applications of high-order and high accurate methods on complex configurations are still limited. One of the main reasons which hinder the widely applications of these methods is the complexity of grids. Many aspects which can be neglected for low-order schemes must be treated carefully for high-order ones when the configurations are complex. In order to implement highorder finite difference schemes on complex multi-block grids, the geometric conservation law and block-interface conditions are discussed. A conservative metric method is applied to calculate the grid derivatives, and a characteristic-based interface condition is employed to fulfil high-order multi-block computing. The fifth-order WCNS-E-5 proposed by Deng [9, 10] is applied to simulate flows with complex grids, including a double-delta wing, a transonic airplane configuration, and a hypersonic X-38 configuration. The results in this paper and the references show pleasant prospects in engineering-oriented applications of high-order schemes.

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“…The concept of non-matching cell faces is not new in CFD and has so far been used by many researchers. References [3,4], amongst others, present the fundamentals of interface conditions for non-matching cell faces. Such methods are nowadays common in turbo-machinery [5], where non-matching and rotating cell faces are used for the simulation of the flow between adjacent blade-rows of aero engines.…”

Section: Introductionmentioning

confidence: 99%

Sliding mesh algorithm for CFD analysis of helicopter rotor–fuselage aerodynamics

Steijl

Barakos

2008

Numerical Methods in Fluids

206

121

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SUMMARYThe study of rotor-fuselage interactional aerodynamics is central to the design and performance analysis of helicopters. However, regardless of its significance, rotor-fuselage aerodynamics has so far been addressed by very few authors. This is mainly due to the difficulties associated with both experimental and computational techniques when such complex configurations, rich in flow physics, are considered. In view of the above, the objective of this study is to develop computational tools suitable for rotor-fuselage engineering analysis based on computational fluid dynamics (CFD).To account for the relative motion between the fuselage and the rotor blades, the concept of sliding meshes is introduced. A sliding surface forms a boundary between a CFD mesh around the fuselage and a rotor-fixed CFD mesh which rotates to account for the movement of the rotor. The sliding surface allows communication between meshes. Meshes adjacent to the sliding surface do not necessarily have matching nodes or even the same number of cell faces. This poses a problem of interpolation, which should not introduce numerical artefacts in the solution and should have minimal effects on the overall solution quality. As an additional objective, the employed sliding mesh algorithms should have small CPU overhead. The sliding mesh methods developed for this work are demonstrated for both simple and complex cases with emphasis placed on the presentation of the inner workings of the developed algorithms.

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A relaxation approach to patched-grid calculations with the Euler equations

Cited by 31 publications

References 6 publications

Computational Analysis of Rotor-Stator Interaction in Turbomachinery Using Zonal Techniques

Computational Analysis of Rotor-Stator Interaction in Turbomachinery Using Zonal Techniques

High-Order and High Accurate CFD Methods and Their Applications for Complex Grid Problems

Sliding mesh algorithm for CFD analysis of helicopter rotor–fuselage aerodynamics

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