A Navier-Stokes Based Strategy for the Aerodynamic Optimisation of a Turbine Cascade Using a Genetic Algorithm

2001 ◽  
Author(s):  
Carlo Cravero ◽  
Antonio Satta
Keyword(s):  
Genetic Algorithm ◽  
Viscous Flow ◽  
Navier Stokes ◽  
Turbine Cascade ◽  
Design Constraints ◽  
Flow Solver ◽  
Flow Computation ◽  
Optimisation Algorithm ◽  
Insight Into

The problem of turbine cascade design is considered using automatic optimisation strategies. After the profile parameterisation, two different models are considered to simulate the cascade performances: experimental correlations and a Navier-Stokes code. Interesting considerations on the optimisation algorithm can be drawn using correlations because the evaluation of the fitness is almost instantaneous. By fixing certain of the design constraints two optimised configurations are obtained using simplified correlating function or the viscous flow solver. The optimised configurations are then investigated with an accurate viscous flow computation in order to have a deeper insight into the flowfield.

Simulation of the Gap Resonance Between Two Rectangular Barges in Regular Waves by a Free Surface Viscous Flow Solver

2013 ◽  
Author(s):  
B. Elie ◽  
G. Reliquet ◽  
P.-E. Guillerm ◽  
O. Thilleul ◽  
P. Ferrant ◽  
...  
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Viscous Flow ◽  
Stokes Equations ◽  
Resonance Phenomenon ◽  
Navier Stokes ◽  
Regular Waves ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Gap Resonance

This paper compares numerical and experimental results in the study of the resonance phenomenon which appears between two side-by-side fixed barges for different sea-states. Simulations were performed using SWENSE (Spectral Wave Explicit Navier-Stokes Equations) approach and results are compared with experimental data on two fixed barges with different headings and bilges. Numerical results, obtained using the SWENSE approach, are able to predict both the frequency and the magnitude of the RAO functions.

Generation of Regular and Irregular Waves in Navier-Stokes CFD Solvers by Matching With the Nonlinear Potential Wave Solution at the Boundaries

2018 ◽  
Author(s):  
Youngmyung Choi ◽  
Benjamin Bouscasse ◽  
Sopheak Seng ◽  
Guillaume Ducrozet ◽  
Lionel Gentaz ◽  
...  
Keyword(s):  
Viscous Flow ◽  
Open Source ◽  
Cfd Simulation ◽  
Irregular Waves ◽  
Navier Stokes ◽  
Wave Fields ◽  
Flow Solver ◽  
Nonlinear Potential ◽  
Simulation Parameters ◽  
2D And 3D

The capability of wave generation and absorption in a viscous flow solver becomes important for achieving realistic simulations in naval and offshore fields. This study presents an efficient generation of nonlinear wave fields in the viscous flow solver by using a nonlinear potential solver called higher-order spectral method (HOS). The advantages of using a fully nonlinear potential solver for the generation of irregular waves are discussed. In particular, it is shown that the proposed method allows the CFD simulation to start at the time and over the space of interest, retrieved from the potential flow solution. The viscous flow solver is based on the open source library OpenFOAM. The potential solvers used to generate waves are the open source solvers HOS-Ocean and HOS-NWT (Numerical Wave Tank). Several simulation parameters in the CFD solver are investigated in the present study. A HOS wrapper program is newly developed to regenerate wave fields in the viscous flow solver. The wrapper program is validated with OpenFOAM for 2D and 3D regular and irregular waves using relaxation zones. Finally, the extreme waves corresponding to the 1000 year return period condition in the Gulf of Mexico are simulated with the viscous flow solver and the wave elevation is compared with the experiments.

scholarly journals Navier-Stokes Computations for Turbulent Flow Predictions in Transonic Turbine Cascade Using a Zonal Approach

1993 ◽  
Author(s):  
J. J. Yeuan ◽  
A. Hamed ◽  
W. Tabakoff
Keyword(s):  
Turbulent Flow ◽  
Viscous Flow ◽  
Turbine Blade ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Turbine Cascade ◽  
Flow Conditions ◽  
Numerical Errors ◽  
Flow Through ◽  
Transonic Turbine

Numerical results are presented for viscous flow through a transonic turbine cascade using different turbulence models and H-type grids. The explicit Navier-Stokes solver used in the solution was developed with an option of conservative zonal approach for interpolation across the periodic boundaries with minimum numerical errors. This approach allows the use of a grid that is more orthogonal and less skewed which leads to higher accuracy in the prediction of turbine blade performance. The results obtained with an algebraic and two equation turbulence models, and with two types of H grids are compared at two different flow conditions.

scholarly journals Secondary Flows in a Transonic Cascade: Validation of a 3-D Navier-Stokes Code

1992 ◽  
Author(s):  
F. Bassi ◽  
M. Savini
Keyword(s):  
Characteristic Feature ◽  
Secondary Flow ◽  
Finite Volume ◽  
Secondary Flows ◽  
Navier Stokes ◽  
Turbine Cascade ◽  
Blade Passage ◽  
Transonic Turbine ◽  
Transonic Cascade ◽  
Insight Into

In this work is presented a finite volume full 3-D Navier-Stokes solver suitable for turbulent turbomachinery computations. The code is applied to the analysis of the secondary flow patterns in a transonic turbine cascade at three different isentropic outlet Mach numbers; namely 0.50, 1.02, 1.38. Detailed measurements obtained in four planes downstream of the trailing edge allow for comparison of losses, flow angles, vorticity and hence for a deep evaluation of the accuracy of the numerical results. Moreover the code is used to gain insight into the formation and the evolution of secondary flows inside the blade passage, into the generation of losses and into characteristic feature of these flows hard to detect experimentally. All the above mentioned aspects are examined and discussed as well as the influence of compressibility, giving thus a precise picture of secondary flows in the transonic regime.

A multigrid and upwind viscous flow solver on 3-D embedded and overlapped grids

1989 ◽  
Author(s):  
OKTAY BAYSAL ◽  
KAMRAN FOULADI ◽  
VICTOR LESSARD
Keyword(s):  
Viscous Flow ◽  
Flow Solver

URANS Studies of Effect of Eccentricity on Ship–Lock Interactions

2016 ◽  
Vol 13 (04) ◽  
pp. 1641012
Author(s):  
Qingjie Meng ◽  
Decheng Wan
Keyword(s):  
Viscous Flow ◽  
Hydrodynamic Interaction ◽  
Vertical Displacement ◽  
Navier Stokes ◽  
Test Case ◽  
The Third ◽  
Surface Pressure Distribution ◽  
Sst Turbulence Model ◽  
Unsteady Viscous Flow ◽  
Ship Lock

The unsteady viscous flow around a 12000TEU ship model entering the Third Set of Panama Locks with different eccentricity is simulated by solving the unsteady Reynolds averaged Navier–Stokes (RANS) equations in combination with the [Formula: see text]SST turbulence model. Overset grid technology is utilized to maintain grid orthogonality and the effects of the free surface are taken into account. The hydrodynamic forces, vertical displacement as well as surface pressure distribution are predicted and analyzed. First, a benchmark test case is designed to validate the capability of the present methods in the prediction of the viscous flow around the ship when maneuvering into the lock. The accumulation of water in front of the ship during entry into a lock is noticed. A set of systematic computations with different eccentricity are then carried out to examine the effect of eccentricity on the ship–lock hydrodynamic interaction.

Simulation of the Transitional Flow in a Low Pressure Gas Turbine Cascade With a High-Order Discontinuous Galerkin Method

2013 ◽  
Vol 135 (7) ◽  
Author(s):  
A. Ghidoni ◽  
A. Colombo ◽  
S. Rebay ◽  
F. Bassi
Keyword(s):  
Discontinuous Galerkin ◽  
Turbulence Model ◽  
Stokes Equations ◽  
Time Integration ◽  
High Order ◽  
Transitional Flow ◽  
Navier Stokes ◽  
Implicit Time ◽  
Turbine Cascade ◽  
High Reynolds

In the last decade, discontinuous Galerkin (DG) methods have been the subject of extensive research efforts because of their excellent performance in the high-order accurate discretization of advection-diffusion problems on general unstructured grids, and are nowadays finding use in several different applications. In this paper, the potential offered by a high-order accurate DG space discretization method with implicit time integration for the solution of the Reynolds-averaged Navier–Stokes equations coupled with the k-ω turbulence model is investigated in the numerical simulation of the turbulent flow through the well-known T106A turbine cascade. The numerical results demonstrate that, by exploiting high order accurate DG schemes, it is possible to compute accurate simulations of this flow on very coarse grids, with both the high-Reynolds and low-Reynolds number versions of the k-ω turbulence model.

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