This study aims to experimentally investigate the effects of parallel blade–vortex interaction (BVI) on the aerodynamic performances of an airfoil, in particular as a possible cause of blade stall, since similar effects have been observed in li...
As a high resolution airload with accurate rotor wake is pivotal for rotor BVI (Blade-vortex interaction) analysis, a hybrid method with combined Navier-Stokes equation, viscous wake model, and FW-H (Ffowcs Williams-Hawkings) equation is developed fo...
The accurate prediction of helicopter rotor blade–vortex interaction (BVI) noise is challenging. This paper presents an implementation of the seventh-order improved weighted essentially non-oscillatory (WENO-Z) scheme for predicting rotor BVI n...
In the design of electric vertical takeoff and landing (eVTOL) vehicles, coaxial rotors have garnered significant attention due to their superior space usage and aerodynamic efficiency compared to standard rotors. However, it is challenging to study...
The air and structural loads of a 5-ton class light helicopter (LH) rotor in a 2.24 g pull-up maneuver are investigated using a coupling between the computational structural dynamics (CSD) and computational fluid dynamics (CFD) methods. The LH rotor...
Dynamic stall is a phenomenon on the retreating blade of a helicopter which can lead to excessive control loads. In order to understand dynamic stall and fill the gap between the investigations on pitching wings and full helicopter rotor blades, a nu...
To clarify the behavior of the blade tip vortices of a wind turbine equipped with a brimmed-diffuser shroud, called a “Wind-Lens turbine”, we conducted a three-dimensional numerical simulation using a large eddy simulation (LES). Since this unique wi...
This study was performed based on the previous work of this research group to promote the practical engineering application of trailing edge flaps. Specifically, the established “intelligent blade” simulation platform was used for simulat...
In order to explore the mechanism during the process of the non-synchronous vibration (NSV), the flow field formation development is investigated in this paper. Based on the fluid–structure interaction method, the vibration of rotor blades is found t...
The inter-blade passage vortex, the vortex rope of the draft tube, and the vortex in the guide apparatus are the characteristics of flow instability of the Francis turbine, which may lead to fatigue failure in serious cases. In the current study, in...
Cavitation is a complex multiphase flow phenomenon, and the generation of transient phase transitions between liquid and vapor during cavitation development leads to multi-scale vortex motion. The transient cavitation dynamics and centrifugal pump&rs...
In order to explore the inducing factors and mechanism of the non-synchronous vibration, the flow field structure and its formation mechanism in the non-synchronous vibration state of a high speed turbocompressor are discussed in this paper, based on...
Cavitation instabilities can induce axial and circumferential vibrations, as well as noise in turbopump inducers. Therefore, the purpose of the present study is to investigate the mechanism of cavitation instability. The flow field near the two-blade...
Vertical-axis wind turbines (VAWTs) offer key advantages such as independence from wind direction, low manufacturing costs, and reduced noise levels, making them highly suitable for urban and offshore wind energy applications. Among various VAWT desi...
This study presents a hybrid non-linear unsteady vortex lattice method-vortex particle method (NL UVLM-VPM) to investigate the aerodynamics of rotor blades hovering in and out of ground effect. The method is of interest for the fast aerodynamic predi...
The formation of an inlet vortex seriously restricts axial-flow pump device performance and poses a great threat to the safe and stable operation of the entire system. In this study, the change trends of an inlet vortex and its influence on an axial-...
In fluid machineries, the flow energy dissipates by transforming into internal energy which performs as the temperature changes. The flow-induced noise is another form that flow energy turns into. These energy dissipations are related to the local fl...
The slots on a blade tip can effectively suppress the tip vortices by diffusing the core structure of a vortex and thus mitigate the adverse impacts of vortex interactions. In this paper, the effect of a slotted tip on vortex diffusion in the hoverin...
In this paper, the tip clearance effects on the aeroelastic stability of a last-stage steam turbine model are investigated. Most of the unsteady aerodynamic work contributing to flutter of the long blades of the last-stage of a steam turbine is done...
In order to develop a sustainable economy based on the efficient use of green energy resources, it is necessary to research and innovate systems such as wind turbines. In this paper, a new configuration for vertical axis wind turbines was proposed an...
Comprehensive rotorcraft simulation codes are the workhorses for designing and simulating helicopters and their rotors under steady and unsteady operating conditions. These codes are also used to predict helicopters’ limits as they approach rot...
Multistage pumps with blade-type guide vanes are widely used in offshore oil production, the petrochemical and coal-chemical industries, and nuclear power fields for its advantages of large flow rate, high pressure, and excellent operation stability....
The leakage flow has a significant impact on the aerodynamic losses and efficiency of the compressor. This paper investigates the loss mechanism in the tip region based on a high-load cantilevered stator cascade. Firstly, a high-fidelity flow field s...
Considering requirements such as enhanced unit capacity, the geometric size of wind turbine blades has been increasing; this, in turn, results in a rapid increase in manufacturing costs. To this end, in this paper, we examine the aerodynamics of co-p...
Nitrogen compression requires centrifugal compressors to operate under relatively high ambient pressure. However, the internal instability characteristics of compressors handling high-density working fluids remain unclear. Therefore, this study emplo...
In unshrouded turbine rotors, the tip leakage vortices develop and interact with the passage vortices. Such complex leakage flow causes the major loss in the turbine stage. Due to the complex turbulence characteristics of the tip leakage flow, the wi...
A panel/vortex particle hybrid method is coupled with a computational structure dynamics code to predict helicopter rotor loads. The rotor blade surfaces and near wakes are modeled by the panel method, while the far wake is modeled by resorting to th...
The tip clearance, a compact gap between the inducer blade tip and casing wall, is critical to both the liquid leakage and cavitation-induced forces of a turbopump. In this study, we numerically investigate the effect of tip clearance on the cavitati...
High payload capacity multi-rotor aerial vehicles are typically configured with multiple propellers to achieve the required aerodynamic lift. However, this design approach often results in an increased overall dimensional envelope, which introduces s...
The passive flow control technology of using splitter blades in low-speed diffuser cascade was investigated in this study. Based on the Reynolds average Navier-Stokes calculations, the arrangement parameters of the splitter blades were studied in det...
The rotor wake aerodynamic characterization is a fundamental aspect for the development and optimization of future rotary-wing aircraft. The paper is aimed at experimentally and numerically characterizing the blade tip vortices of a small-scale four-...
Both scientific and industrial communities have a growing interest in marine renewable energies. There is a wide variety of technologies in this domain, with different degrees of maturity. This study focuses on two models of a mast-free vertical axis...
When a pump-jet propeller rotates at high speeds, a tip vortex is usually generated in the tip clearance region. This vortex interacts with the main channel fluid flow leading to the main energy loss of the rotor system. Moreover, operating at a high...
1 August 2023
In the current study, full-stage unsteady simulations were performed to investigate rotating instability inception mechanisms in a particularly large tip clearance centrifugal compressor with a vaneless diffuser and a volute. Four operating points al...
Efficient prediction of aerodynamic loads on wind turbine blades under yawed inflow remains challenging due to the complexity of three-dimensional unsteady flow phenomena. In this work, a modified blade element momentum (BEM) method, incorporating mu...
This study addresses the challenge of performance degradation in waterjet pumps due to non-uniform suction flow. Utilizing the Proper Orthogonal Decomposition (POD) method, it decomposes and reconstructs the flow features within a waterjet pump under...
The outlet duct is the only outlet flow component of the pump as turbines (PATs). The flow state within it not only affects its operation stability but also influences the safe operation of downstream process equipment. The undesirable flow phenomeno...
The performance of a wind turbine generator (WTG) is highly dependent on the interaction of a rotor blade with complex fluid behaviors, especially the induced vortex structure. In this paper, vortical flows around a blade were first investigated by t...
A numerical study was conducted on winglet designs with multiple sweep angles for improving the performance of horizontal axis wind turbine (HAWT) blades, and their effect on reducing the wing tip vortex was investigated by CFD analysis. The effects...
The Computational Fluid Dynamics (CFD) method is used to analyze the transient flow patterns and vortex evolution during the startup process of a novel tulip-type hydraulic turbine rotor. The model is validated with experimental results for the rotor...
The operating state of a pump-turbine unit under no-load conditions is directly related to its safe and stable operation. In order to probe into the influence of hydraulic characteristics on structural performance, a pump-turbine assembled in China i...
The steady and unsteady flow characteristics of internal flow in a backward centrifugal fan of double inlet at low flow-rate condition are investigated by computational fluid dynamics in this paper. The investigation aims to reveal insights into gene...
Current trends show that wind turbines are growing in size to meet a rising demand for renewable energy generation, and their upscaled rotors have inherently become more flexible to maintain a proportionally lighter design. This is because larger rot...
Tip leakage flow interacts with the mainstream, impacting the energy transmission process within the impeller of the fan and causing a significant flow loss. Understanding the flow characteristics within the impeller is a prerequisite and foundation...
22 November 2022
The effect of blade sweep has been studied numerically with the Lattice Boltzmann Method on a family of low-speed free-vortex axial fans with sweeps of ±45°. Good overall aerodynamic agreement is first demonstrated on all fans at the desig...
An open-source 2D Reynolds-averaged Navier–Stokes (RANS) simulation model was presented and applied for a laboratory-scaled cross-flow hydrokinetic turbine and a twin turbine system in counter-rotating configurations. The computational fluid dynamics...
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...
Francis turbines are widely used due to their large capacity and broad head adaptability, placing higher demands on the internal flow characteristics and runner performance of the units. In this paper, numerical simulations of a Francis turbine model...
Vertical axis wind turbines (VAWTs) are gradually receiving more and more interest due to their lower sensitivity to the yawed wind direction. Compared with straight blades VAWT, blades with a certain helicity show a better aerodynamic performance an...
This study develops a hybrid solver with reversed overset assembly technology (ROAT), a viscous vortex particle method (VVPM), and a CFD program based on the URNS method, in order to study the aerodynamic and acoustic characteristics of coaxial rigid...
of 3