A series of three-dimensional unsteady Reynolds-averaged Navier–Stokes (RANS) simulations are conducted to investigate the formation of stall cells over a pitching NACA 0012 aerofoil. Periodic boundary conditions are applied to the spanwise end...
The hydrodynamic investigation of a hull’s performance is a key aspect when designing a new prototype, especially when it comes to a competitive/racing environment. This paper purports to perform a fully nonlinear unsteady Reynolds Averaged Nav...
A hybrid Reynolds-averaged Navier Stokes/large-eddy simulation (RANS/LES) turbulence model integrated with a transition formulation is developed and tested on a surrogate model problem through a joint experimental and computational fluid dynamic appr...
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 occurrence of cavitation in marine propellers is a major source of noise in ships. Consequently, the occurrence and noise characteristics of cavitation must be better understood to control this issue. This study focuses on identifying the occurre...
The goal of this study is to compare mainstream Computational Fluid Dynamics (CFD) with the widely used 1D transient model LedaFlow in their ability to predict riser induced slug flow and to determine if it is relevant for the offshore oil and gas in...
In this study, the Reynolds-averaged Navier–Stokes (RANS) method and a model experimental test in a towing tank are used to investigate the unsteady hydrodynamic performance of L-type podded propulsion under different oblique flow angles and ad...
In the present work, a generic ducted azimuth propulsor, which are frequently installed on a wide range of vessels, is subject to numerical investigation with the primary focus on performance deterioration and dynamic loads arising from the influence...
This paper addresses the long-standing question of understanding the origin and evolution of low-frequency unsteadiness interactions associated with shock waves impinging on a turbulent boundary layer in transonic flow (Mach: 1.1 to 1.3). To that end...
The aerodynamic performance of bridge deck girders requires a thorough assessment and optimization in the design of long-span bridges. The present paper describes a numerical investigation of the aerodynamic characteristics of a twin-box bridge girde...
Herein, we compare the drag area estimated using unsteady Reynolds-averaged Navier-Stokes (URANS), using the γ−ReΘ transitional shear stress transport (SST) k−ω (SSTLM) turbulence model with published experimental measurements of a static full-scale...
Close-packed contra-rotating vertical-axis turbines have potential advantages in wind and hydrokinetic power generation. This paper describes the development of a numerical model of a vertical axis turbine with a torque-controlled system using an act...
To study the three-dimensional effects on the dynamic-stall characteristics of a rotor blade, the unsteady flowfields of the finite wing and rotor were simulated under dynamic-stall conditions, respectively. Unsteady Reynolds-averaged Navier–St...
21 August 2019
New propulsive concepts, such as boundary layer ingestion, involve stronger interactions between the engine and its environment, and are thus more complex flows compared to classical architectures. Usual turbomachinery design tools are inadequate, an...
This paper handles a hybrid multiple optimization technique to concurrently enhance hydraulic efficiency and decrease unsteady radial forces resulting from fluid-induced vibration of a single-channel pump for wastewater treatment. A single-channel im...
In this paper, the characteristics of the cyclone separator was analyzed from the Lagrangian perspective for designing the important dependent variables. The neural network network model was developed for predicting the separation performance paramet...
Dam-break flood waves represent a severe threat to people and properties located in downstream regions. Although dam failure has been among the main subjects investigated in academia, little effort has been made toward investigating wave propagation...
9 February 2018
Secondary flow and loss development in the T106Div-EIZ low-pressure turbine cascade are investigated utilizing (U)RANS simulations in cases with and without periodically incoming wakes at M a 2 t h = 0 . 59 and R e 2 t h = 2 × 10...
Unsteady Reynolds-averaged Navier–Stokes simulations of an axial-flow pump for waterjet propulsion are carried out at model scale, and the numerical uncertainties are analyzed mainly according to the procedure recommended by the twenty-eighth I...
This paper discusses the results of computational fluid dynamics simulations carried out for rectangular cylinders with various side ratios of interest for many civil engineering structures. A bridge deck of common cross-section geometry was also con...
A new Partially Averaged Navier-Stokes (PANS) bridging model is derived from existing (k−ω) and (k−ε) PANS formulations. The model behaves like the PANS (k−ω) model near rigid walls and like the PANS (k−&ep...
Consumer products contain chemical substances that threaten human health. The zero-dimensional modeling methods and experimental methods have been used to estimate the inhalation exposure concentration of consumer products. The model and measurement...
Dam-break wave propagation usually occurs over irregular topography, due for example to natural contraction-expansion of the river bed and to the presence of natural or artificial obstacles. Due to limited available dam-break real-case data, laborato...
The performance of a transonic high pressure turbine is mainly influenced by the unsteady interactions associated with the passing blades. In this paper, the unsteady flow interactions in a transonic turbine have been numerically investigated using t...
Large-eddy simulation (LES) and Reynolds-Averaged Navier–Stokes (RANS) equations were used to study incompressible flow and heat transfer in a U-duct with a high-aspect-ratio trapezoidal cross section. For the LES, the WALE subgrid-scale model...
Gas turbines are important energy-converting equipment in many industries. The flow inside gas turbines is very complicated and the knowledge about the flow loss mechanism is critical to the advanced design. The current design system heavily relies o...
The objective of the paper is to demonstrate the importance of the unsteady Computational Fluid Dynamics (CFD) simulations and long-term measurements for the reliable assessment of thermal comfort indoors, for proper categorization of the indoor ther...
26 August 2020
The present study focuses on the impact of the underlying RANS turbulence model in the Zonal Detached Eddy Simulation (ZDES) method when used for secondary flow prediction. This is carried out in light of three issues commonly investigated for hybrid...
The present results are focused on the self-sustained oscillations of a confined impinging slot jet and their role in the flow structure and modeling requirements. Unsteady laminar, large-eddy simulation (LES), and Reynolds-averaged Navier–Stok...
Unsteady separation is a phenomenon that occurs in many flows and results in increased drag, decreased lift, noise emission, and loss of efficiency or failure in flow devices. Turbulence models for the steady or unsteady Reynolds-averaged Navier&ndas...
Tip leakage vortex (TLV) in a transonic compressor rotor was investigated numerically using detached-eddy simulation (DES) method at different working conditions. Strong unsteadiness was found at the tip region, causing a considerable fluctuation in...
Characterization of unsteady loads is critical for the development of control systems for next-generation air vehicles. Both Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) methods are prohibitively expensive, and existing Reynolds-...
In this article, the performance of a radial flow turbine is determined in the framework of oscillating water column installations (OWC). The studied turbine redesigned and adapted from previous studies to this application, is analyzed in detail usin...
Accurate prediction of pollutant dispersion is vital to the energy industry. This study investigated the Computational Fluid Dynamics (CFD) simulation of pollutant emission in a natural draft dry cooling tower (NDDCT) with flue gas injection. In orde...
In the present work, the three-dimensional heat and fluid flows around staggered pin-fin arrays are predicted using two hybrid RANS/LES models (an improved delayed detached eddy simulation (IDDES) model and a stress-blended eddy simulation (SBES) mod...
27 August 2021
The flow in a transonic turbine stage still poses a high challenge for the correct prediction of turbulence using an eddy viscosity model. Therefore, an unsteady RANS simulation with the k-ω SST model, based on a preceding study of turbulence inlet c...
10 November 2023
This paper presents the numerical characterization of a highly loaded compressor by means of 3D unsteady RANS simulations. The focus is on critical flow structures and their evolution at different operating points of the machine. First, the numerical...
The intent of shielding functions in delayed detached-eddy simulation methods (DDES) is to preserve the wall boundary layers as Reynolds-averaged Navier–Strokes (RANS) mode, avoiding possible modeled stress depletion (MSD) or even unphysical separati...
Hydrodynamic coefficient estimation is crucial to the shape design, dynamic modeling, and control of underwater vehicles. In this paper, we conduct a numerical study on the hydrodynamic coefficient estimation of an underactuated underwater vehicle (a...
This paper compares the performances of three Computational Fluid Dynamics (CFD) turbulence models, Reynolds Average Navier-Stokes (RANS), Detached Eddy Simulation (DES), and Large Eddy Simulation (LES), for simulating the flow field of a wheel loade...
13 November 2023
The successful design of compressor blades through numerical optimization relies on accurate CFD-RANS solvers that are able to capture the general performance of a given design candidate. However, this is a difficult task to achieve in transonic flow...
This paper presents an unsteady flow analysis of a 3D wing with a morphing trailing edge flap (TEF) and a seamless side-edge transition between the morphed and static parts of a wing by introducing an unsteady parametrization method. First, a 3D stea...
The accurate prediction of blade tip vortices continues to be challenging for the investigation of rotor aerodynamics. In the current work, the blade tip vortex system of a Caradonna–Tung rotor in the hovering state is simulated on account of t...
Traditional hybrid RANS/LES methods often struggle to accurately capture both the boundary layer transition and flow separation simultaneously due to their reliance on fully turbulent RANS models. To address this limitation, the present study first e...
Mixing characteristics of multi-chambered contact tank are analyzed employing the validated three-dimensional numerical model developed in the companion paper. Based on the flow characterization, novel volumetric mixing efficiency definitions are pro...
The unsteady flow characteristics and responses of an NACA 0012 airfoil fitted with a bio-inspired morphing trailing edge flap (TEF) at near-stall angles of attack (AoA) undergoing downward deflections are investigated at a Reynolds number of 0.62 ×...
The simulation of very small vertical axis wind turbines is often a complex task due to the very low Reynolds number effects and the strong unsteadiness related to the rotor operation. Moreover, the high boundary layer instabilities, which affect the...
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...
In this paper, a numerical assessment of the effect of shallow water on the total resistance of the solar catamaran SolarCat is carried out using computational fluid dynamics within the software package STAR–CCM+. The unsteady viscous fluid flo...
To investigate the impact of different computational strategies on the self-propulsion hydrodynamic performance of a submarine model, a study was conducted using the RANS method, employing both the steady-state Moving Reference Frame (MRF) method and...
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