Autor: Kwiatkowski, T. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Source term model for streamwise Rod Vortex Generator modelling
Autorzy:: Kwiatkowski, T.
Flaszyński, P.
Powiązania:: https://bibliotekanauki.pl/articles/244365.pdf
Data publikacji:: 2016
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: source term model
rod vortex generator
streamwise vortices
flow control
BAY model
BAY method
Opis:: In the article, the new method of modelling of Rod Vortex Generators (RVGs) was proposed. RVGs are inclined rods, mounted in boundary layer used to flow control. RVGs were intensively investigated in Institute of Fluid-Flow Machinery in Gdansk, Poland. The research results indicate high potential of RVGs to flow control in wide range of Mach numbers (Mach 0.3-1.45) in the main flow. Due to the flow structure details generated by RVG, it is required to create fine grids in the vicinity of RVGs, which increase the computational cost. In order to overcome this difficulty and reduce computational cost the new numerical models of RVGs are proposed, which use the modification of BAY model. Using BAY model it is not needed to resolve the shape of RVG in detail and it is possible to use orthogonal meshes. The BAY model was originally proposed to predict flows behind thin-plate vortex generators. This model works by adding momentum source term to Reynolds-Averaged Navier-Stokes equations in ANSYS Fluent. The BAY model spatial vectors orientation was modified and some simplifications were performed. The model was calibrated and simulations were carried out for the single rod. The results and effectiveness of modified BAY model were compared with wind-tunnel experiment results and grid-resolved model.
Źródło:: Journal of KONES; 2016, 23, 4; 261-268
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Analysis of effects of shape and location of micro-turbulators on unsteady shockwave-boundary layer interactions in transonic flow
Autorzy:: Sznajder, J.
Kwiatkowski, T.
Powiązania:: https://bibliotekanauki.pl/articles/242878.pdf
Data publikacji:: 2016
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: transonic flow control
laminar-turbulent transition
flow simulations
aircraft engineering
transport
vehicles
Opis:: Solutions for turbulisation of a part of laminar boundary layer upstream of shockwave on laminar airfoil in transonic flow were investigated by means of solution of Unsteady Reynolds-Averagd Navier-Stokes equations using as a closure the four-variable Transition SST turbulence model of ANSYS FLUENT solver. This turbulence model has the capability of resolving laminar-turbulent transition occurring in undisturbed flow as well as under the influence of flow-control devices. The aim of the work was to investigate possibilities of improvement of aerodynamic characteristics of laminar wing of a prospective transport aircraft in adverse conditions characterised by occurrence of a shockwave over a laminar-turbulent transition region with separation of laminar flow under the shockwave. The subject is important for application of laminar flow technology, offering economic and environmental advantages due to decreased friction drag, into civil transport aviation. Natural laminar-turbulent transition in the investigated conditions takes place with occurrence of “laminar separation bubble” under the foot of a shockwave and the resulting shockwave is intensive and prone to unsteady oscillations, the “buffet” phenomenon, limiting operational range of flight parameters. In order to counteract the harmful effects of natural laminar-turbulent transition in transonic flow two types of turbulators, placed upstream of the shockwave, were investigated. One of them consisted of delta-shaped vortex generators, producing chordwise-oriented vortices. The other consisted of rectangular micro-vanes, perpendicular to flow and to airfoil surface producing vortices of rotation axes oriented spanwise. Effectiveness of both types of turbulators was investigated for varying height and their location on airfoil chord. Both types of turbulators have proved their effectiveness in tripping laminar boundary layer. The specific effects of the tutbulators, different for each type occurred in the region where laminar separation takes place on clean airfoil. As a result, the changes of lift and drag were different for each type of turbulators.
Źródło:: Journal of KONES; 2016, 23, 2; 373-380
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Effects of turbulence induced by micro vortex generators on shockwave : boundary layer interactions
Autorzy:: Sznajder, J.
Kwiatkowski, T.
Powiązania:: https://bibliotekanauki.pl/articles/245222.pdf
Data publikacji:: 2015
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: transonic flow control
laminar-turbulent transition
vortex generators
flow simulations
BAY method
Opis:: Interactions between viscous and transonic effects in air flow around a laminar wing were investigated computationally by means of the solution of unsteady Reynolds-averaged Navier-Stokes Equations. The subject is important from the point of view of applications of Natural Laminar Flow technology in modern, economically efficient passenger aircraft. The research was focused on simulations and analyses of influence of turbulence induced by micro vortex generators on intensity of harmful transonic phenomena like strong shock waves and buffet. Two ways of modelling of the effects of turbulators – the micro vortex generators were taken into consideration. The first way consisted in resolving the shape and inclination angle of the generator in the grid over airfoil and setting the non-slip wall boundary condition on the surface of the generator. The second way, taking advantage of the BAY model of vortex generator, was implemented on orthogonal grid without the need of resolving the shape of the vortex generator in the grid. Calibration of the BAY model was aimed at producing similar distribution of vorticity and velocity circulation behind the model of the vortex generator, as obtained for the grid-resolved model of the vortex generator. The calibration procedure resulted, however, in overestimated turbulisation of the boundary layer in the BAY model, compared to the effects of the grid-resolved vortex generator. The flow simulations indicated, however, that turbulisation of boundary layer induced by micro vortex generators can reduce or eliminate the oscillation of strong shock wave and buffet in off-design conditions and that further adjusting of the BAY model is an efficient strategy for modelling the interactions between viscous and transonic effects in air flow around a laminar wing.
Źródło:: Journal of KONES; 2015, 22, 2; 241-248
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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