Multigrid calculations of a jet in crossflow

Abstract

In order to assess accurately the standard k-e model in a three-dimensional recirculating flow, a series of numerical calculations of a jet in a crossflow have been made employing progressively fine finite-difference meshes consisting of up to 2.4 million grid nodes. The discretized equations have been solved with a blockimplicit multigrid algorithm that is observed to converge efficiently. The calculated velocity and turbulence fields are compared with experimental data. It is observed that the general features of the flow are well predicted, but there are appreciable discrepancies between measured and calculated values. Even with current fine resolution, the calculation cannot be said to be completely grid independent; however, the major disagreements are believed to result from the turbulence model.

Multigrid acceleration and turbulence models for computations of 3D turbulent jets in crossflow

“…Significant differences exist only near the mid-plane at 6D, but at 8D the results are quite close. The differences are much smaller than those reported by Claus and Vanka [12] in their study of a row of jets in crossflow. The differences are also small in comparison with deviations from experimental data.…”

“…Due to computational expense, none of the earlier studies use sufficiently fine grids. In a recent paper, Claus and Vanka [12] present a systematic study of the effect of grid resolution on the mean flow and turbulence fields. These show that for computational grids up to 96 X 96 X 256 grid-independent solutions could not be obtained.…”

LES of turbulent jet in cross-flow: Part 1 – A numerical validation study

“…From initial attempts of numerical simulations based on vortex methods of Margason (1969) and Coelho and Hunt (1989), Cortelezzi and Karagozian (2001) among others to RANS based calculations of e.g. Sykes et al (1986), Alvarez and Jones (1993), Claus and Vanka (1992), Demuren (1993) and more recent LES based computations of e.g. Jones and Wille (1996), Yuan et al (1999), Schluter and Schonfeld (2000), Ziefle and Kleiser (2009) and DNS studies of e.g.…”

Computational fluid dynamics prediction of intake ingestion relevant to short take-off and vertical landing aircraft

“…In the last decade extensive experimental and computational studies have been conducted to study the fluid mechanics of single and multiple impinging jets with and without crossflow. References [9] to [29] have provided general reviews of current understanding of attempts to compute these flowfields.…”

“…However, since their primary motivation was the behaviour of the jet remote from the wall, they did not attempt to resolve details of the wake region. Claus and Vanka [29] presented a series of calculations which attempted to study the grid-independent behaviour of the k±å model for jet-incrossflow problems. Up to 2.5 million grid nodes were used; their study indicated that, for calculations employing a first-order scheme, grid independence is probably impossible to achieve, even with grids as fine as this.…”