Conditioning and accurate solutions of Reynolds average Navier–Stokes equations with data-driven turbulence closures

2021 ◽  
Vol 915 ◽  
Author(s):  
Bernardo P. Brener ◽  
Matheus A. Cruz ◽  
Roney L. Thompson ◽  
Rodrigo P. Anjos
Keyword(s):  
Stokes Equations ◽  
Data Driven ◽  
Navier Stokes ◽  
Reynolds Average Navier Stokes ◽  
Navier Stokes Equations ◽  
Turbulence Closures ◽  
Reynolds Average

Abstract

Dynamic Stall Control by Undulatory Deformation

2013 ◽  
Vol 444-445 ◽  
pp. 299-303
Author(s):  
Lan Ge ◽  
Wen Rong Hu
Keyword(s):  
Stokes Equations ◽  
Dynamic Stall ◽  
Navier Stokes ◽  
Reynolds Average Navier Stokes ◽  
Navier Stokes Equations ◽  
Stall Angle ◽  
Stall Control ◽  
Reynolds Average ◽  
High Angles Of Attack ◽  
Better Than

Dynamic stall can delay the stall of wings and airfoils that are rapidly pitched beyond the static stall angle. A new method of active dynamic stall control by the undulatory foil was proposed in this paper. The study was based on solving unsteady Reynolds-Average Navier-Stokes equations. Comparisons of the effectiveness of pitching foils and undulatory foils on dynamic stall control in both light stall and deep stall were conducted. The undulatory foils with various controllable parameters were further discussed. The results showed that the performance of undulatory foils is much better than that of the rigid pitching foil at high angles of attack either in the light stall or in the deep stall situation.

Hydrodynamic design of an advanced submerged propulsion

2019 ◽  
Vol 233 (18) ◽  
pp. 6367-6382
Author(s):  
Jing-Wei Jiang ◽  
Wei-Xi Huang
Keyword(s):  
Stokes Equations ◽  
Navier Stokes ◽  
Design Parameters ◽  
Reynolds Average Navier Stokes ◽  
Navier Stokes Equations ◽  
Mathematical Algorithm ◽  
Cavitation Performance ◽  
Intermediate Section ◽  
Thrust And Torque ◽  
Reynolds Average

A new kind of advanced submerged propulsion is automatically modeled and analyzed based on the hydrodynamic and cavitation performance. A mathematical algorithm is proposed to describe the fusion-duct, which is controlled by several design parameters, including section diameters, section lengths, and inlet shape and aspect ratio. The hydrodynamic performances of 13 cases with different parameter combinations are numerically simulated. The simulation is carried out by solving the Reynolds Average Navier-Stokes equations with STAR-CCM+, and the SST k-ω turbulence model is applied. The curves of rotor thrust and torque, stator thrust and duct resistance, along with efficiency and merit coefficient are obtained as functions of the advance coefficient and are compared for different cases. Meanwhile, the pressure distribution on both sides of the rotor and the flow field of intermediate section are systematically analyzed. To guide future designs, an impact factor is further defined and calculated to quantify the effects of different parameters. The results indicate that the section diameters have the most significant influence on hydrodynamic and cavitation performances.

Effect of Turbulence Modeling on VIV Numerical Simulation

2005 ◽  
Author(s):  
Juan B. V. Wanderley ◽  
Gisele H. B. Souza ◽  
Carlos Levi
Keyword(s):  
Numerical Method ◽  
Compressible Flows ◽  
Turbulence Modeling ◽  
Stokes Equations ◽  
Turbulence Models ◽  
Circular Cylinders ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Reynolds Average

Author’s previous work Wanderley [1] presented an efficient numerical method to investigate VIV phenomenon on circular cylinders. The numerical model solves the unsteady Reynolds Average Navier–Stokes equations for slightly compressible flows using the Beam–Warming implicit factored scheme. In the present work, the effect of the turbulence model on the results is evaluated for both Baldwin Lomax and k-ε models. To demonstrate the quality of the numerical method, results for the transversal oscillation of a cylinder laterally supported by spring and damper are compared with experimental data. The application of the turbulence models showed the much better agreement of the k-ε model with the experimental results.

Analysis of Loads and Response on Flexible Riser under the Combined Effects of Wave and Current

2015 ◽  
Vol 723 ◽  
pp. 120-124 ◽  
Author(s):  
Zi Xin Wu ◽  
Ren Qing Zhu ◽  
Si Qi Gu ◽  
Zhi Ping Xia ◽  
Yang Luo ◽  
...  
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Flexible Riser ◽  
Navier Stokes Equations ◽  
Volume Method ◽  
System Coupling ◽  
Reynolds Average ◽  
Viscid Fluid ◽  
Module System

A three dimensional computational model is established for the analysis of loads and response of flexible riser in a wave-current coexisting environment. The viscid fluid is assumed incompressible. The flow field is described by continuity equation and Reynolds Average Navier-Stokes equations and solved with the discretization of Finite-Volume Method. The structure responses are analyzed employing finite element method based on three dimensional solid element. The loads and response are calculated through the CFD module System Coupling in software package ANSYS14.5. The results show that the vibration equilibrium position of riser offsets along with the direction of current when wave and current are in the same direction, the response of the riser is larger than that only in wave, the vibration amplitude increases with the current and the results are opposite to the above when wave and current has the opposite direction.

Numerical Study on the Effect of Tandem Spacing on Flow Induced Motions of Two Cylinders With Passive Turbulence Control

2015 ◽  
Author(s):  
Lin Ding ◽  
Li Zhang ◽  
Chunmei Wu ◽  
EunSoo Kim ◽  
Michael M. Bernitsas
Keyword(s):  
Stokes Equations ◽  
Numerical Study ◽  
Circular Cylinders ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Turbulence Control ◽  
Frequency Responses ◽  
Simulation Results ◽  
Passive Turbulence Control ◽  
Reynolds Average

The effect of tandem spacing on the flow induced motions (FIM) of two circular cylinders with passive turbulence control is investigated using two-dimensional Unsteady Reynolds-Average Navier-Stokes equations with the Spalart-Allmaras turbulence model. Results are compared to experiments in the range of Reynolds number of 30,000<Re<100,000. The center-to-center spacing between the two cylinders is varied from 2 to 6 diameters. Simulation results predict well all ranges of FIM including VIV and galloping and match well with experimental measurements. For the upstream cylinder, the amplitude and frequency responses are not considerably influenced by the downstream cylinder when the spacing is greater than 2D. For the downstream cylinder, a rising amplitude trend in the VIV upper branch can be observed in all cases as is typical of flows in the TrSL3 regime. The galloping branch merges with the VIV upper branch for spacing greater than 3D. Vortex structures show significant variation in different flow regimes in accordance with experimental observations. High-resolution post-processing shows that the interaction between the wakes of cylinders result in various types of FIM.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

Sign in / Sign up

Export Citation Format

Share Document