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김사량;유정열
- Transactions of the Korean Society of Mechanical Engineers
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- v.19 no.9
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- pp.2297-2307
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- 1995
An experimental study on the structure of a separated shear layer downstream of the backward-facing step has been performed by examining mean flow and turbulent quantities in terms of free stream turbulence. When free stream turbulence exists, the entrainment rate of the separated shear layer and the flow rate in the recirculation region are enhanced, resulting in shorter reattachment length. The production and diffusion terms in the turbulent kinetic energy balance are shown to increase more than the dissipation term does. Rapid decrease of the pressure-strain term in the shear stress balance implies the enhancement of the three-dimensional motion by free stream turbulence.
https://doi.org/10.22634/KSME.1995.19.9.2297 인용 PDF

Kim J. W.;Park J. W.
- 한국전산유체공학회:학술대회논문집
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- 2003.08a
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- pp.165-170
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- 2003
Centrifugal blowers are widely used for air handling units in industry applications. The blower has a centrifugal impeller and a scroll casing including a driving component such as an electric motor. The impeller takes forward or backward blades to induce flows into the blower. Comprehensive investigation according to the two kinds of blades is systematically carried out for a guidance of design. It is observed that flow rate of the blower with forward blades is larger than that of the system with backward blades. The reason is due to larger velocity from the rotating forward blades and the tendency is validated by a parallel experiment with a wind tunnel. Numerical analysis for the system shows detail information inside the blades and the casing. A series of figures to show the flow details offers deep understanding of a centrifugal blower with different blades.
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;;Oh, Myung-Taek
- Transactions of the Korean Society of Mechanical Engineers
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- v.19 no.11
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- pp.3014-3021
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- 1995
This study is carried out in order to evaluate the performances of the Reynolds stress turbulence models such as SSG and GL models in the calculation of separated flow over backward-facing stepp.In addition, two slow return-to-isotropy models, YA and Rotta models combined with rapid part of SSG model are also tested. The finite volume method is used to discretize the governing differential equations, and the power-law scheme is used to approximate the convection terms. The SIMPLE algorithm is used for pressure correction in the governing equations. The results show that SSG model gives the better prediction near the reattachment point than GL model. In cases that the rapid term of SSG model is combined with Rotta and YA slow models, the results show the better predictions of stress components in recirculation zone, but indicate inaccuracy in the predictions of mean velocity.
https://doi.org/10.22634/KSME.1995.19.11.3014 인용 PDF