A comprehensive review, CFD and ML analysis of flow around tandem circular cylinders at sub-critical Reynolds numbers

Journal of Wind Engineering and Industrial Aerodynamics, Год журнала: 2025, Номер 257, С. 105998 - 105998

Опубликована: Янв. 8, 2025

Язык: Английский

---

Afterbody longitudinal cavities for drag reduction and application of artificial neural network for optimization of groove geometry

Physics of Fluids, Год журнала: 2025, Номер 37(3)

Опубликована: Март 1, 2025

The boattail model was found as an effective passive device for reducing the aerodynamic drag of axisymmetric models. For further decreasing drag, groove cavities made on region show a high potential technique. In this study, geometry longitudinal considered to understand its effect model. Then, artificial neural network (ANN) developed predict total find configuration with minimum drag. that purpose, Reynolds-averaged Navier–Stokes k-ω shear stress transport is used simulation. To generate data ANN, automatic program create geometry, build mesh, and conduct calculation. computational results were validated by experiments same flow conditions. baseline cases, decreases angles 14°, then, it increases again. However, changing grooves, up 20° maximum reduction 34% in comparison blunt-based mechanism due modification surface from full separation case attached small local bubbles when made. pressure significantly increase second-half models fully separated added. below distribution at rear part remains similar grooves. ANN present can be predicted well averaged uncertainty less than 2%. A characteristics are presented.

Язык: Английский

---

Three-dimensional wake transition of rectangular cylinders and temporal prediction of flow patterns based on a machine learning algorithm

Physics of Fluids, Год журнала: 2024, Номер 36(9)

Опубликована: Сен. 1, 2024

This study investigates the three-dimensional (3D) wake transition in unconfined flows over rectangular cylinders using direct numerical simulation (DNS). Two different cross-sectional aspect ratios (AR) and Reynolds numbers (Re) are scrutinized: AR = 0.5 at Re 200 3 600. The investigation focuses on characterizing flow patterns forecasting their temporal evolution utilizing proper orthogonal decomposition (POD) technique coupled with a long short-term memory (LSTM) network. DNS results reveal emergence of an ordered mode A for 3, attributed to stabilizing effect elongated AR. On other hand, case smaller (= 0.5) exhibits mode-swapping regime characterized by modes B's distinct simultaneous manifestation. spanwise wavelengths B approximately 4.7 1.2 D 0.5, while wavelength is 3.5 3. POD serves as dimensionality reduction technique, LSTM facilitates prediction. algorithm demonstrates satisfactory performance predicting patterns, including instabilities B, across both transverse directions. employed adeptly predicts pressure time series surrounding cylinders. duration training only about 0.5% required computations. research, first time, effectiveness POD–LSTM complex 3D instantaneous past

Язык: Английский

---

Experimental study on cylinder wake control using forced rotation

Journal of Wind Engineering and Industrial Aerodynamics, Год журнала: 2024, Номер 246, С. 105662 - 105662

Опубликована: Фев. 5, 2024

Язык: Английский

---

Consideration of Aspect Ratios on Flow Around Wall-mounted Square Cylinders

Journal of Marine Science and Application, Год журнала: 2025, Номер unknown

Опубликована: Май 2, 2025

Язык: Английский

---

Flow characteristics and passive flow control of circular cylinders with triangular vortex generators: An experimental investigation

Applied Ocean Research, Год журнала: 2023, Номер 142, С. 103836 - 103836

Опубликована: Дек. 9, 2023

Язык: Английский

---

Wake Structures and Hydrodynamic Characteristics of Flows around Two Near-Wall Cylinders in Tandem and Parallel Arrangements

Journal of Marine Science and Engineering, Год журнала: 2024, Номер 12(5), С. 832 - 832

Опубликована: Май 16, 2024

To clarify the hydrodynamic interference characteristics of flows around multiple cylinders under wall effect, two-dimensional (2D) near-wall single, two tandem and parallel are simulated different gap ratios (0.15 ≤ G/D 3.0) spacing (1.5 T/D 4.0) at a Reynolds number Re = 6300. We also examine wake patterns, force coefficients, vortex-shedding frequency with emphases on effect effects two-cylinder interference. A critical 0.6 is identified in single-cylinder case where can exert significant influences. The exhibit three states: stretching mode, attachment impinging mode. coefficients upstream cylinder significantly affected by for 0.6. downstream mainly influenced cylinder. For > 0.6, similar variation trend. In arrangement, four states ranges: double hetero-vortex scale unilateral vortex free Moreover, or mode have synchronous in-phase state out-of-phase state. mean drag decrease, while lift opposite trends, as grows.

Язык: Английский

---

Machine learning approach to predict flow fields induced by internal solitary waves acting on mid-water structures based on particle image velocimetry experiments

Ocean Engineering, Год журнала: 2024, Номер 309, С. 118326 - 118326

Опубликована: Июнь 12, 2024

Язык: Английский

---

The groove effect on wake characteristics of rotating cylinders

Physics of Fluids, Год журнала: 2024, Номер 36(7)

Опубликована: Июль 1, 2024

In the present study, active and passive flow control methods have been implemented to investigate their effects on wake structures of a circular cylinder. Grooves having circular, rectangular, triangular cross sections applied cylinders exposed rotation rates, α, from 0 0.79. The experiments conducted by particle image velocimetry at Reynolds number Re = 5 × 103. contour graphics time-averaged results presented. Moreover, variations in velocity profiles also depicted. experimental revealed significant for patterns, structures, turbulence parameters due both groove geometries rotational motion. stationary cases, intensity, grooved cylinder exhibited 15% increase, while showed slightly higher increase around 20% compared that bare (BC). Conversely, non-stationary rectangular displayed most prominent reduction decreasing approximately 10% BC. type has considerably affected regions, especially lower rates.

Язык: Английский

---

Drag reduction by the effect of rounded corners for a square cylinder

Physics of Fluids, Год журнала: 2024, Номер 36(9)

Опубликована: Сен. 1, 2024

Flow around square cylinders has been studied via unsteady simulations done at a Reynolds number of Re = 100. In the present study, effects rounded corners on different flow characteristics have evaluated. The main influence considered for various ratios (r*) up to 0.45 in terms drag coefficient values. stagnation points obtained front cylinders. These constitute maximum pressure. cluster sizes cross-stream velocity components are nearly same. Viscous generates vortices top and bottom edges cylinder. produced affected by wake region. When moving away from bodies, streamwise profiles influenced variation corner ratios. region shrunk owing corners, reduction provided. (CD) as 1.418 r* 0. As result increasing ratio coefficients decreased percentage values 4.6%, 7.2%, 8.4%, 9.6%, 11.1%, 11.9%, 12.5%, 13.3%, 14.3% decrement 0.05 when compared reference value. most effective value attained 4.6% row. Even though tends increase enhancing increment rate indicates decreasing trend.

Язык: Английский

---