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Amano, R. S.

Publications and source records attributed to Amano, R. S..

25 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Development of a turbulence near-wall model and its application to separated and reattached flows

A numerical study is reported of flow and heat transfer in the separated and reattached flows created by an abrupt pipe expansion. In the study attention has been given primarily to the development of turbulence near-wall models based on the wall function. An efficient numerical method is also employed for the computation of high-velocity flows. The computed results are compared with experimental data obtained earlier. Generally, better results are obtained by employing the present near-wall models, and among them the three-layer model is superior to the two-layer one.

Amano, R. S.↗
NASA NTRS1984

Turbulent heat transfer in a channel with two right-angled bends

A numerical study is reported on the flow and heat transfer in a channel with two right-angled bends. The k-epsilon turbulence model with a refined near-wall model is adopted for the computation of the flow field for step ratios ranging H/W = 1-4 and for Reynolds numbers Re = 3,000-10,000. The solution method of the governing transport equations is based on the modified hybrid scheme which produces very small truncation error. As a result of extensive computations, the complex flow patterns in the channel with two bends are clarified and the mechanisms of heat transfer are explained relating to the flow behaviors of separation, deflection, recirculation, and reattachment.

Amano, R. S.↗
NASA NTRS1983

Numerical study of a separating and reattaching flow by using Reynolds-stress tubulence closure

The numerical study of the Reynolds-stress turbulence closure for separating, reattaching, recirculating and redeveloping flow is summarized. The calculations were made for two different closure models of pressure - strain correlation. The results were compared with the experimental data. Furthermore, these results were compared with the computations made by using the one layer and three layer treatment of k-epsilon turbulence model which were developed. Generally the computations by the Reynolds-stress model show better results than those by the k-epsilon model, in particular, some improvement was noticed in the redeveloping region of the separating and reattaching flow in a pipe with sudden expansion.

Amano, R. S.↗
NASA NTRS1983

Turbulent heat transfer in the separated reattached and redevelopment regions of a circular tube

A numerical study is reported on a flow in a circular pipe with an abrupt expansion. In this paper the behavior of flow in the domain including recirculating and redeveloping regions has been reviewed carefully and a new grid system is employed which provides finer grids in the recirculating region and monotonically expanding grids in the redeveloping region. The predicted results were improved for the class of this flow by incorporating and adapting the low-Reynolds number model of turbulence throughout the solution domain. The computational results obtained by the present model generally are better than the former results of the authors, particularly in the prediction of the reattachment points.

Amano, R. S.↗
NASA NTRS1982

Turbulent transport modeling of shear flows around an aerodynamic wing. Development of turbulent near-wall model and its application to recirculating flows

Progress in implementing and refining two near-wall turbulence models in which the near-wall region is divided into either two or three zones is outlined. These models were successfully applied to the computation of recirculating flows. The research was further extended to obtaining experimental results of two different recirculating flow conditions in order to check the validity of the present models. Two different experimental apparatuses were set up: axisymmetric turbulent impinging jets on a flat plate, and turbulent flows in a circular pipe with a abrupt pipe expansion. It is shown that generally better results are obtained by using the present near-wall models, and among the models the three-zone model is superior to the two-zone model.

Amano, R. S.↗
NASA NTRS1982

On the calculation of turbulent heat and mass transport downstream from an abrupt pipe expansion

A numerical study is reported of heat/mass transfer in the separated flow region created by an abrupt pipe expansion. Computations have employed a hybrid method of central and upwind finite differencing to solve the full Navier-Stokes equations with turbulent model (k approximately equal to epsilon). The study has given its main attention to the simulation of the region in the immediate vicinity of the wall, by formulating near-wall model for the evaluation of the mean generation and destruction rate of the epsilon equation. The computed results were compared with the experimental data and they showed generally encouraging agreement with the measurements.

Amano, R. S.↗