The physics of heat and mass transfer from an object in its wake has significant importance in natural phenomena as well as across many engineering applications. Here, we report numerical results on the population density of the spatial distribution...
In this study, deep neural network (DNN) and transfer learning (TL) techniques were employed to predict the viscous resistance and wake distribution based on the positions of flow control fins (FCFs) applied to containerships of various sizes. Both m...
In this study, the optimal design of flow control fins (FCFs) for a container ship was carried out via a machine learning approach. The conventional design practice for the FCF relied on simulation-based performance evaluation, which demands a large...
The k-omega SST turbulence model is extensively employed in Reynolds-averaged Navier–Stokes (RANS)-based Computational Fluid Dynamics (CFD) calculations. However, the accuracy of the estimation of viscous resistance and companion flow distribut...
The flow in rivers is turbulent. The main parameter related to turbulence in rivers is the eddy viscosity, which is used to model a turbulent flow and is involved in the determination of both velocities and sediment concentrations. A well-known and l...
Ice accretion on arctic vessels and offshore platforms poses serious threats to navigation and operational safety. Existing research has primarily focused on isolated structures. This study employs a combined approach of numerical simulation and expe...
The wakes of wall-mounted small (square) and large (long) depth-ratio rectangular prisms are numerically studied at Reynolds numbers of 50–250. The large depth-ratio significantly alters the dominance of lateral secondary flow (upwash and downwash) i...
Propeller designers often need to base their design on the nominal model scale wake distribution because the effective full scale distribution is not available. The effects of such incomplete design data on cavitation performance are examined in this...
Numerical simulation is carried out to investigate the effect of the boundary condition of two lateral end-plate walls on the flow structure in the wake of a flow crossing a yawed circular cylinder. Two typical boundary conditions, nonslip and period...
Panel methods have been applied to many fields of fluid owing to their computational efficiency. However, their applications are limited in simulating highly turbulent flow with separations due to the inviscid flow assumptions, such as those associat...
A numerical study of atmospheric turbulence effects on wind-turbine wakes is presented. Large-eddy simulations of neutrally-stratified atmospheric boundary layer flows through stand-alone wind turbines were performed over homogeneous flat surfaces wi...
In general, computational fluid dynamics (CFD) models incur high computational costs when dealing with realistic and complicated flows. In contrast, the mass-consistent flow (MASCON) field model provides a three-dimensional flow field at reasonable c...
In a compressor, the periodic wake is an inherently unsteady phenomenon that affects the downstream flow conditions and loading distribution. Thus, understanding the physical mechanisms of these unsteady effects is important for eliminating flow loss...
This work presents a new engineering analytical model that predicts the effect of both the turbine yaw misalignment and the inflow wind veer on the wake flow distribution downwind of a wind turbine. To consider the veered inflow, two methods were exa...
In the present work, the turbulent wake of a circular cylinder in a confined flow environment at a blockage ratio of 14% is experimentally investigated in a wind tunnel consisting of a parallel test section followed by a constant-area distorting duct...
Aquatic vegetation in rivers and coastal regions controls the flow structure in terms of mean velocity and turbulence. The vegetation in the flow affects the transportation of nutrients, microbes, dissolved oxygen, sediment, and contaminants; therefo...
The harnessing and utilization of tidal current energy have emerged as prominent topics in scientific inquiry, due to their vast untapped resource potential, leading to numerous investigations into the efficacy of hydrokinetic turbines under various...
This study systematically investigated the aerodynamic characteristics of a closed box girder in sinusoidal oscillating flow fields based on experimental and numerical approaches. The numerical method was validated through comparison with experimenta...
In order to understand the wake characteristics for the circular cylinder with the dimpled structure, particle image velocimetry (PIV) and proper orthogonal decomposition (POD) method are used to measure and analyze the flow field velocity and the fl...
The environment for the shipboard landing and takeoff of helicopters is extremely complex and significantly affects their safe flight. To address the intricate characteristics of the flow field during these operations, a simulation method suitable fo...
The uniformity of the wake on the submarine propeller disk is the key factor affecting the vibration and noise performance of the propeller. To study the influence of the fillets on the uniformity of submarine wake field and propeller unsteady bearin...
In this paper, the spatiotemporal evolution of wind turbine (WT) wake characteristics is studied based on lattice Boltzmann method-large eddy simulations (LBM-LES) and grid adaptive encryption at different incoming flow velocities. It is clearly capt...
This work presents a comparison study of the CFD modeling with two different turbulence modeling approaches viz. unsteady RANS and LES, on a full-scale model of the (New) MEXICO rotor wind turbine. The main emphasis of the paper is on the rotor and w...
The present work presents numerical research on the wake flows behind a propeller operating under three advance coefficients. Large eddy simulations are adopted to obtain the viscous flow information behind the propeller. In particular, the study hig...
In the present study, multiple-fan active control wind tunnel tests are conducted to investigate the aerodynamic forces on a 5:1 rectangular cylinder in sinusoidal streamwise winds with different angles of attack (AoA). The effects of the frequency,...
An electrically controlled rotor (ECR) is a kind of swashplateless rotor that implements the primary control via the trailing-edge flap system instead of a swashplate and demonstrates great potential in vibration reduction and noise alleviation. In t...
In this study, large eddy simulation (LES) is combined with a turbine model to investigate the wake behind a vertical-axis wind turbine (VAWT) in a three-dimensional turbulent flow. Two methods are used to model the subgrid-scale (SGS) stresses: (a)...
In this paper, the entire process of the flow around a fixed square cylinder and the moving surface boundary-layer control (MSBC) at a low Reynolds number was numerically simulated. Two small rotating circular cylinders were located in each of the tw...
Low-fidelity engineering wake models are often combined with linear superposition laws to predict wake velocities across wind farms under steady atmospheric conditions. While convenient for wind farm planning and long-term performance evaluation, suc...
13 September 2023
The influence of unsteady wakes incoming from the upstream stages is of high relevance in modern high-speed, low-pressure turbines (LPT) operating at transonic exit Mach numbers and low Reynolds numbers for their potential to trigger transition and i...
Future wind power developments may be located in complex topographic and harsh environments; forests are one type of complex terrain that offers untapped potential for wind energy. A detailed analysis of the unsteady interaction between wind turbines...
In this study, an analytical wake model for predicting the mean velocity field downstream of a wind turbine under veering incoming wind is systematically derived and validated. The new model, which is an extended version of the one introduced by Bast...
A 2D numerical simulation was conducted to investigate the effect of an extended rigid trailing edge fringe with a flapping motion on the S833 airfoil and its wake flow field, as an analogy of an owl’s wing. This study aims to characterize the...
The haze-fog particle dispersion in urban communities will cause serious health and environmental problems, which has aroused society attention. The aim of the present investigation is to reveal the underlying mechanisms of haze-fog particle dispersi...
A hypothesis was tested and validated for predicting the vortex strength induced by a vortex generator in wall-bounded flow by combining the knowledge of the Vortex Generator (VG) geometry and the approaching boundary layer velocity distribution. In...
Isothermal turbulent flow around circular cylinders arranged side-by-side was numerically simulated on a commercial finite-volumes platform, ANSYS® CFX, version 2020 R2. The turbulence was modeled by using k-ω shear stress transport (k-&ome...
Unsteady pressure-sensitive paint (i-PSP) measurements were performed at a sampling rate of 30 kHz to investigate the near-endwall blade suction surface flow inside a low-pressure turbine cascade operating at engine-relevant high-speed and low-Re con...
Many bottom-mounted offshore wind farms are currently planned for the coastal areas of Japan, in which wind speeds of 6.0–10.0 m/s are extremely common. The impact of such wind speeds is very relevant for the realization of bottom-mounted offshore wi...
An experimental investigation of active flow control on a three-dimensional (3D) curved surface bluff body was conducted by using a string-type plasma actuator. The 3D bluff body model tested in this study was composed of a quarter sphere and a half...
In this study, the large eddy simulation method and the actuator line model are used to investigate the wake redirection of two turbines. Different turbine spacings and yaw-based control of the upstream turbine are considered. The effects of yaw angl...
A time-stepping, lifting-line, computationally efficient tool for preliminary design applications is developed to predict the unsteady aerodynamic loads of rotors operating in hovering and axial flight. The velocity field induced by wake vorticity is...
Flow structure is a crucial point for the conceptual design of Wing-in-Ground effect (WIG) crafts. In this study, pressure distributions around a compound wing, velocity and the turbulent intensity distribution in the wake area after trailing of the...
This study investigated the power production and blade fatigue of a three-turbine array subjected to active yaw control (AYC) in full-wake and partial-wake configurations. A framework of a two-way coupled large eddy simulation (LES) and an aeroelasti...
An optimized three-bladed horizontal-axis miniature wind turbine, called WiRE-01, with the rotor diameter of 15 cm is designed and fully characterized in Part I of this study. In the current part of the study, we investigate the interaction of the tu...
The podded propulsor has gradually become an important propulsion device for high technology ships in recent years because of its characteristics of high maneuverability, high efficiency, low noise, and vibration. The performance of podded propulsor...
The geometry of a conventional two-bladed Savonius rotor was used in this study based on a report available in the literature. A two-dimensional rotor model consisting of two buckets and an overlap ratio of 0.1 was prepared. The unsteady Reynolds ave...
The operation of the wind turbines downstream is affected by the wake of the wind turbines upstream. Wind turbine wake flow is investigated by applying the actuator disc (AD) method. The modified k-ε turbulence model is proposed by using both...
The wake dynamics of sharp-edge rigid panels is examined using Overset Grid Assembly (OGA) utilized in OpenFOAM, an open-source platform. The OGA method is an efficient solution technique based on overlap of a single or multiple moving grids on a sta...
This study numerically investigates laminar flow around two prismatic bodies, specifically square cylinders, arranged in tandem. The analysis covered gap ratios (L/D=2–7) and Reynolds numbers (Re = 100–200), focusing on quantifying the ae...
Ladle metallurgy is an important steelmaking technology in high-quality steel production. The blowing of argon at the ladle bottom has been applied in ladle metallurgy for several decades. Until now, the issue of breakage and coalescence among bubble...
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