| 131. |
- Kozlov, V.V., et al.
(författare)
-
Breakdown of a streak via development of varicose secondary mode on the straight wing with pressure gradient
- 2006
-
Ingår i: In Laminar-Turbulent Transition. Proc. of Sixth IUTAM Symposium, Bangalore, India 2004. ; , s. 419-424
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In the present experimental work, which utilizes a hot-wire visualization method, an influence of external pressure gradient on the development of secondary instabilities in the straight wing boundary layers has been demonstrated for the first time. The comparison of experimental data and direct numerical simulation results of this process has been given.
|
|
| 132. |
|
|
| 133. |
|
|
| 134. |
- Litvinenko, Artem, 1989, et al.
(författare)
-
A spinwave Ising machine
- 2023
-
Ingår i: Communications Physics. - 2399-3650. ; 6:1
-
Tidskriftsartikel (refereegranskat)abstract
- Time-multiplexed Coherent Ising Machines (CIMs) have demonstrated promising results in rapidly solving large-scale combinatorial problems. However, CIMs remain relatively large and power-demanding. Here, we demonstrate a spinwave-based Ising machine (SWIM) that due to the low spinwave group velocity allows for sufficient miniaturization and reduced power consumption. The SWIM is implemented using a 10-mm-long 5-mu m-thick Yttrium Iron Garnet film with off-the-shelf microwave components and can support an 8-spin MAX-CUT problem and solve it in less than 4 mu s consuming only 7 mu J. As the SWIM minimizes its energy, we observe that the spin states can demonstrate both uniform and domain-propagation-like switching. The developed SWIM has the potential for substantial further miniaturization with reduction of power consumption, scalability in the number of supported spins, increase of operational speed, and may become a versatile platform for commercially feasible high-performance solvers of combinatorial optimization problems.
|
|
| 135. |
- Litvinenko, Yu.A., et al.
(författare)
-
Adverse pressure gradient effect on nonlinear varicose instability of a streaky structure in an unswept wing boundary layer
- 2005
-
Ingår i: Physics of Fluids. ; 17
-
Tidskriftsartikel (refereegranskat)abstract
- Nonlinear varicose instability of a streaky structure is experimentally investigated in a wing boundary layer. Spatial evolution of the streaky structure perturbed by high-frequency traveling waves is compared at zero and adverse streamwise pressure gradients. The process of streak multiplication and generation of ?-shaped vortices is under examination. Results obtained testify to the strong influence of pressure gradient upon the breakdown of the streaky structure due to its varicose instability.
|
|
| 136. |
|
|
| 137. |
|
|
| 138. |
- Litvinenko, Yu.A., et al.
(författare)
-
Control of spanwise flow instability of a swept wing by suction
- 2003
-
Ingår i: Thermophysics and Aeromechanics. ; 10:4, s. 541-548
-
Tidskriftsartikel (refereegranskat)abstract
- The experimental results on control by disturbances development in a swept wing boundary layer by means of localized and distributed suction are presented. The control by spanwise flow stationary vortices and secondary periodical disturbances generated at late stages of these vortices development was studied. It is shown that the distributed suction is a simple way to suppress the secondary vortex instability of a spanwise flow as compared with a localized suction. It was shown that the localized suction through a small diameter hole may cause generation of additional stationary vortices in the boundary layer. In this case complex nonlinear interactions between both controlled and controlling disturbances take place. The distributed suction effect through a group of holes is similar to the slot suction and it introduces much less disturbances of vorticity into the boundary layer.
|
|
| 139. |
- Litvinenko, Yu.A., et al.
(författare)
-
Experimental investigation of a streaky structure varicose instability in a swept wing boundary layer
- 2004
-
Ingår i: Thermophysics and Aeromechanics. ; 11:1, s. 13-22
-
Tidskriftsartikel (refereegranskat)abstract
- The investigation results of the controlled experiment of a streaky structure varicose instability in a swept wing boundary layer are presented. The picture of a streaky structure spatial evolution and secondary high-frequency disturbances generated on it is obtained using hot-wire measurements. It is shown that exactly a varicose instability is realized. It has been found that the secondary disturbance increases owing to instability of mean velocity distribution on normal to the wall caused by the streaky structure development. The following features of a varicose breakdown of a longitudinal stationary streaky structure are presented: structure modulation in the longitudinal direction by a secondary disturbance frequency, downstream excitation of new streaky structures, formation and development of nonstationary structures localized in space. In contrast to the boundary layer flow of the unswept wing models, where these structures resemble classical horseshoe structures or lambda-vortices, only one vortex remains on a swept wing from the two making the vortex structure because of the crossflow.
|
|
| 140. |
|
|
