tailieunhanh - PARTICLE-LADEN FLOW - ERCOFTAC SERIES Phần 6

Tham khảo tài liệu 'particle-laden flow - ercoftac series phần 6', ngoại ngữ, anh ngữ phổ thông phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Numerical particle tracking studies in a turbulent round jet Giordano Lipari David D. Apsley and Peter K. Stansby School of Mechanical Aerospace and Civil Engineering - University of Manchester -Manchester - M60 1QD - UK 1 Overview This paper discusses numerical particle tracking of a 3D cloud of monodisperse particles injected within a steady incompressible free round turbulent jet. With regard to particle-turbulence interaction the presented modeling is adequate for dilute suspensions 7 as the carrier and dispersed phase s solutions are worked out in two separate steps. Section 2 describes the solution of the carrier fluid s Reynolds-averaged flow. The Reynolds numbers of environmental concern are generally high and here the turbulence closure is a traditional k-e model a la Launder and Spalding 2 with an ad hoc correction of Pope s to the e equation to account for circumferential vortex stretching in a round jet 21 . The resulting mean-flow and Reynolds-stress fields are discussed in the light of the LDA measurements by Hussein et al. 1994 with Re 105 11 . Section 3 deals with the solution of the dispersed phase. The carrier fluid s unresolved turbulence is modeled as a Markovian process. We particularly refer to the reviews of Wilson Legg and Thomson 1983 30 and McInnes and Bracco 1992 18 . Clouds of marked fluid particles rather than trajectories are used for visualizing the dispersing power of fluctuations. As fluctuations in inhomogeneous turbulence are known to entail sizeable spurious effects the consistency of the Eulerian and Lagrangian statistics are checked by comparing the first- and second-order moments of the particle velocity with the mean flow and Reynolds stresses of the Eulerian solution as well as the concentration fields from either solution. Surprisingly our tests failed to confirm the full effectiveness of the corrections proposed in either model. The particle spurious mean-velocity vanishes towards the jet edge .