International Journal of Heat and Mass Transfer, Год журнала: 2023, Номер 216, С. 124533 - 124533
Опубликована: Авг. 2, 2023
Язык: Английский
Journal of Energy Storage, Год журнала: 2024, Номер 96, С. 112731 - 112731
Опубликована: Июнь 24, 2024
Язык: Английский
Процитировано
10
Energy, Год журнала: 2023, Номер 289, С. 130086 - 130086
Опубликована: Дек. 20, 2023
Язык: Английский
Процитировано
19
Journal of Fluid Mechanics, Год журнала: 2023, Номер 966
Опубликована: Июль 5, 2023
In the gap region of tandem cylinders, within reattachment regime, bi-stability is seen to be cellular. Direct numerical simulations at a Reynolds number 500, and ratio 3.0, show that shedding vortices occurs in spanwise cells, with lengths between 0.3 2.7 cylinder diameters. These unstable vortex cells tend asymmetric respect centreline, so are repeatedly shed from just one shear layer for several periods. The appear basic cell structure dictated by three-dimensional instability, their do not exceed those cells. Unstable intermittently become coherent, this leads significant increase drag amplitude. mode change associated low-frequency variation separation points on downstream cylinder, causing modulation formation length.
Язык: Английский
Процитировано
11
Ocean Engineering, Год журнала: 2025, Номер 319, С. 120274 - 120274
Опубликована: Янв. 4, 2025
Язык: Английский
Процитировано
0
AIP Advances, Год журнала: 2025, Номер 15(2)
Опубликована: Фев. 1, 2025
Vortex-induced vibration (VIV) to capture low-velocity water current energy has broad application prospects. To utilize hydrokinetic on a large scale, the structure should be composed of multiple cylinders. In this paper, harvested from with two three-dimensional cylinder oscillators in tandem arrangement driven by VIV is simulated range reduced velocity Ur = 2–13. The entropy production theory applied evaluate loss quantitatively and analyze correlation between dissipation upstream downstream Combined Liutex’s third-generation vortex identification method, coupling evolution process cylinders obtained. results show following: (1) amplitude response both shows three distinct branches. (2) maximum efficiencies are 40.53% 37.71%, respectively. Peak power efficiency observed primarily upper branch, diminishing after transitioning lower branch eventually approaching zero. (3) main turbulent (EPTD) caused turbulence dissipation, collision, accounts for largest proportion, up more than 99%, while rate direct close 0 can negligible. increases exponentially, resulting significant decrease captured PVIV ηVIV local wall shear stress larger formation smaller shedding. variations reflect strength interaction fluid structure, consequently reflecting ability oscillators.
Язык: Английский
Процитировано
0
International Journal of Mechanical Sciences, Год журнала: 2022, Номер 227, С. 107437 - 107437
Опубликована: Июнь 9, 2022
Язык: Английский
Процитировано
8
AIP Advances, Год журнала: 2024, Номер 14(4)
Опубликована: Апрель 1, 2024
The separation and turbulent transition of the flow in a compressor blade channel are investigated through direct numerical simulations (DNS) at Reynolds number 1.367 × 105. Based on original DNS data, both time-averaged statistics instantaneous vortex structures field extensively analyzed. vortices visualized studied by Liutex method, streaming dynamic mode decomposition (SDMD), low-storage variant conventional DMD, is applied to large datasets obtained pressure suction sides. physical quantity analyzed with SDMD magnitude R. results indicate that occurs sides blade. On surface, weak remains natural dominated viscous Tollmien–Schlichting instabilities. In contrast, owing presence laminar bubble, experiences governed inviscid Kelvin–Helmholtz instabilities surface. suggest broad range frequencies exist flow, scale spatial negatively correlated frequency mode. extracted modes primarily related rolls, whereas side, influenced separated boundary layer, modal exhibit greater diversity.
Язык: Английский
Процитировано
1
Journal of Fluid Mechanics, Год журнала: 2023, Номер 976
Опубликована: Дек. 7, 2023
Flow around curved tandem cylinders in the convex configuration has been studied by means of direct numerical simulations, for a Reynolds number 500 and nominal gap ratio 3.0. Spanwise variation flow regimes, as well curvature-induced axial velocity, leads to an exceedingly complex vortex dynamics wake. Both parallel oblique shedding are observed. Oblique is connected repeated occurrences dislocations. The dislocations caused two main mechanisms: frequency differences upper part geometry vortices into lower near types closely associated with mode switch gap. In parts gap, there low-frequency quasi-periodic asymmetry vortices, where biased one side intervals several wake periods. from surge vertical similar that long-term recirculation length
Язык: Английский
Процитировано
3
AIAA SCITECH 2022 Forum, Год журнала: 2023, Номер unknown
Опубликована: Янв. 19, 2023
View Video Presentation: https://doi.org/10.2514/6.2023-1009.vid The tandem arrangement of wings is commonly encountered in nature and engineering due to its unique aerodynamic benefits. Therefore, studying their interactions' characteristics mechanisms the key understanding fluid motions. This paper uses three-dimensional direct numerical simulations (DNS) two stationary NACA0012 at an attack angle α = 4˚ a low Reynolds number 10,000 based on third-generation vortex identification method liutex visualize coherent structures patterns. time-averaged results reveal that back wing has apparent advantages over front one with increased lift decreased drag. Regarding variation coefficients, dominant frequency both identical comes from periodic shedding vortices trailing edge tips. More low-frequency modes are found hind wing's coefficient spectrum turbulent interferences upstream vortices. Moreover, instantaneous flow field could explain benefits related separation, reattachment, evolution.
Язык: Английский
Процитировано
1
International Journal of Heat and Mass Transfer, Год журнала: 2023, Номер 216, С. 124533 - 124533
Опубликована: Авг. 2, 2023
Язык: Английский
Процитировано
0