In-Flight Receptivity Experiments on a 30-degree Swept-Wing Using Micron-sized Discrete Roughness Elements

In the article using a liquid crystal thermography investigated the development of stationary and secondary disturbances, which were excited by cylindrical and two-dimensional roughness elements. It was shown, that two-dimensional roughness element has a destabilizing effect on disturbances, induced by cylindrical roughness element. Also the twodimensional roughness element is able to excite the stationary structures, and then the secondary disturbances the frequency interval of which is lower than in the case of stationary vortices excitation by cylindrical roughness element

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Influence of two-dimensional roughness element on boundary layer structure in the favourable pressure gradient region of the swept wing

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410019841776 ◽

2019 ◽

Vol 234 (1) ◽

pp. 20-27

Author(s):

Stepan Tolkachev ◽

Victor Kozlov ◽

Valeriya Kaprilevskaya

Keyword(s):

Boundary Layer ◽

Pressure Gradient ◽

Layer Structure ◽

Roughness Element ◽

Three Dimensional ◽

Two Dimensional ◽

Frequency Range ◽

Swept Wing ◽

Boundary Layer Structure ◽

Roughness Elements

In this article, the results of research about stationary and secondary disturbances development behind the localized and two-dimensional roughness elements are presented. It is shown that the two-dimensional roughness element has a destabilizing effect on the disturbances induced by the three-dimensional roughness element lying upstream. In this case, the two-dimensional roughness element causes the appearance of stationary structures, and then secondary perturbations, whose frequency range lies lower than in the case of the stationary vortices excited by a three-dimensional roughness element.

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Natural convection in an enclosure with discrete roughness elements on a vertical heated wall

International Journal of Heat and Mass Transfer ◽

10.1016/0017-9310(88)90251-7 ◽

1988 ◽

Vol 31 (7) ◽

pp. 1423-1430 ◽

Cited By ~ 46

Author(s):

S. Shakerin ◽

M. Bohn ◽

R.I. Loehrke

Keyword(s):

Natural Convection ◽

Heated Wall ◽

Roughness Elements ◽

Discrete Roughness Elements

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Control of a swept-wing boundary layer using ring-type plasma actuators

Journal of Fluid Mechanics ◽

10.1017/jfm.2018.195 ◽

2018 ◽

Vol 844 ◽

pp. 36-60 ◽

Cited By ~ 8

Author(s):

Nima Shahriari ◽

Matthias R. Kollert ◽

Ardeshir Hanifi

Keyword(s):

Boundary Layer ◽

Cross Flow ◽

Plasma Actuators ◽

Swept Wing ◽

Ring Type ◽

Transition Control ◽

Turbulent Transition ◽

Roughness Elements ◽

Order Of Magnitude ◽

Induced Velocity

Application of ring-type plasma actuators for control of laminar–turbulent transition in a swept-wing boundary layer is investigated thorough direct numerical simulations. These actuators induce a wall-normal jet in the boundary layer and can act as virtual roughness elements. The flow configuration resembles experiments by Kim et al. (2016 Technical Report. BUTERFLI Project TR D3.19, http://eprints.nottingham.ac.uk/id/eprint/46529). The actuators are modelled by the volume forces computed from the experimentally measured induced velocity field at the quiescent air condition. Stationary and travelling cross-flow vortices are triggered in the simulations by means of surface roughness and random unsteady perturbations. Interaction of vortices generated by actuators with these perturbations is investigated in detail. It is found that, for successful transition control, the power of the actuators should be increased to generate jet velocities that are one order of magnitude higher than those used in the experiments by Kim et al. (2016) mentioned above.

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