3D Simulation of a Convergent-Divergent Aero Engine Intake, Using Two Different CFD Methods

2005 ◽  
Author(s):  
Ioannis Templalexis ◽  
Pericles Pilidis ◽  
Geoffrey Guindeuil ◽  
Theodoros Lekas ◽  
Vassilios Pachidis
Keyword(s):  
Vortex Lattice ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Internal Flow ◽  
Navier Stokes ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Aero Engine ◽  
Flow Effects ◽  
Development And Validation

This study refers to the development and validation of a Three Dimensional (3D) Vortex Lattice Method (VLM) to be used for internal flow case studies and more precisely aero-engine intake simulation. It examines the quantitative and qualitative response of the method to a convergent – divergent intake, produced as a surface of revolution of the CFM56-5B2 upper lip geometry. The study was carried out for three different sections namely: Intake outlet, intake throat and intake inlet. Moreover five different settings of Angle Of Attack (AOA) were considered. The VLM was based on an existing code. It was modified to accommodate internal flow effects and match, as closely as possible, the boundary conditions set by the Reynolds Average Navier-Stokes (RANS) Computational Fluid Dynamics (CFD) simulation. In the context of this study, Vortex Lattice-derived average values velocity profiles were compared against RANS CFD results.

Aero Engine Axi-Symmetric Convergent-Constant Area Intake 3D Simulation Using a Panel Method Approach

2005 ◽  
Author(s):  
Ioannis Templalexis ◽  
Pericles Pilidis ◽  
Geoffrey Guindeuil ◽  
Petros Kotsiopoulos ◽  
Vassilios Pachidis
Keyword(s):  
Three Dimensional ◽  
Internal Flow ◽  
Navier Stokes ◽  
Lattice Method ◽  
Simulation Code ◽  
Lower Lip ◽  
Vortex Lattice Method ◽  
Constant Area ◽  
Computational Fluid Dynamics Cfd ◽  
General Effort

This study has been carried out as a part of a general effort to develope a powerful simulation code, based on the Vortex Lattice Method (VLM), capable of simulating adequately accurate and comparatively fast, internal flow regimes. It utilizes a convergent – (nearly) constant area axi-symmetric intake three dimensional geometry, emerged as a surface of revolution from the CFM56-5B2 lower lip geometry. The study focuses on the three most critical planes, which are the inlet of the intake, the outlet of the diverging section and the outlet of the intake. Moreover, the sensitivity of the simulation on the variation of the Angle Of Attack (AOA) is tested for four different settings equally spaced, ranging from 0 to 20 degrees. The comparison is carried out on both two-dimensional velocity distributions and average values. The VLM simulation code was based on an existing code, which was modified in order to be adapted to the Reynolds Average Navier-Stokes (RANS) Computational Fluid Dynamics (CFD) boundary conditions.

Database of Sail Shapes vs. Sail Performance and Validation of Numerical Calculation for Upwind Condition

2007 ◽  
Author(s):  
Yutaka Masuyama ◽  
Yusuke Tahara ◽  
Toichi Fukasawa ◽  
Naotoshi Maeda
Keyword(s):  
Numerical Method ◽  
Vortex Lattice ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Numerical Calculations ◽  
Navier Stokes ◽  
Coupling Scheme ◽  
Aerodynamic Coefficients ◽  
Lattice Method ◽  
Cfd Method

Database of full-scale three-dimensional sail shapes are presented with the aerodynamic coefficients for the upwind condition of IMS type sails. Three-dimensional shape data are used for the input of numerical calculations and the results are compared with the measured sail performance. The sail shapes and performance are measured using a sail dynamometer boat Fujin. The Fujin is a 34-foot LOA boat, in which load cells and charge coupled devices (CCD) cameras are installed to measure the sail forces and shapes simultaneously. The sailing conditions of the boat, such as boat speed, heel angle, wind speed, wind angle, and so on, are also measured. The tested sail configurations are as follows: mainsail with 130% jib, mainsail with 75% jib and mainsail alone. Sail shapes are measured at several height positions. The measured shape parameters are chord length, maximum draft, maximum draft position, entry angle at the luff and exit angle at the leech. From these parameters three-dimensional coordinates of the sails are calculated by interpolation. These three-dimensional coordinates are tabulated with the aerodynamic coefficients. Numerical calculations are performed using the measured sail shapes. The calculation methods are of two types; Reynolds-averaged Navier-Stokes (RANS)-based CFD and vortex lattice methods (VLM). A multi-block RANS-based CFD method was developed by one of the authors and is capable of predicting viscous flows and aerodynamic forces for complicated sail configuration for upwind as well as downwind conditions. Important features of the numerical method are summarized as follows: a Finite- Analytic scheme to discretize transport equations, a PISO type velocity-pressure coupling scheme, multi-block domain decomposition capability, and several choices of turbulence models depending on flows of interest. An automatic grid generation scheme is also included. Another calculation method, the vortex lattice method is also adopted. In this case, step-by-step calculations are conducted to attain the steady state of the sail in steady wind. Wake vortices are generated step-by-step, which flow in the direction of the local velocity vector. These calculated sail forces are compared with the measured one, and the validity of the numerical method is studied. The sail shape database and comparison with numerical calculations will provide a good benchmark for the sail performance analysis of the upwind condition of IMS type sails.

Thruster and FPSO Hull Interaction

2014 ◽  
Author(s):  
Ye Tian ◽  
Spyros A. Kinnas
Keyword(s):  
Experimental Data ◽  
Hybrid Method ◽  
Computational Efficiency ◽  
Vortex Lattice ◽  
Numerical Results ◽  
Navier Stokes ◽  
Dynamic Positioning ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Number Of Cells

A hybrid method which couples a Vortex-Lattice Method (VLM) solver and a Reynolds-Averaged Navier-Stokes (RANS) solver is applied to simulate the interaction between a Dynamic Positioning (DP) thruster and an FPSO hull. The hybrid method could significantly reduce the number of cells to fifth of that in a full blown RANS simulation and thus greatly enhance the computational efficiency. The numerical results are first validated with available experimental data, and then used to assess the significance of the thruster/hull interaction in DP systems.

Numerical Approach to Aeroelastic Responses of Three-Dimensional Flexible Sails

1993 ◽  
Author(s):  
Toichi Fukasawa ◽  
Masanobu Katori
Keyword(s):  
Numerical Simulations ◽  
Vortex Lattice ◽  
Three Dimensional ◽  
Numerical Approach ◽  
The Finite Element Method ◽  
Lattice Method ◽  
3 Dimensional ◽  
Vortex Lattice Method ◽  
Induced Drag ◽  
Displacement Theory

Aeroelastic responses of 3-dimensional flexible sails are investigated by means of numerical simulations. An incremental finite displacement theory using the Finite Element Method is adopted to describe the structural behavior of the sail. A modified Vortex Lattice Method is used to calculate the aerodynamic pressures on the sail. Combining these two methods, the structural and aerodynamic responses of the sail are solved simultaneously. Numerical simulations are performed for actual 3- dimensional sails. Deformations and stresses of the sail in steady flow are calculated. Unsteady sail dynamics are also investigated in the case where the sailing vessel is pitching and rolling in a seaway. The effects of the flexibility of the sail upon the lift, induced drag and the center of effort are clarified.

Prediction of Unsteady Effective Wake by a Euler Solver/Vortex-Lattice Coupled Method

2003 ◽  
Vol 47 (02) ◽  
pp. 131-144
Author(s):  
Jin-Keun Choi ◽  
Spyros A. Kinnas
Keyword(s):  
Vortex Lattice ◽  
Three Dimensional ◽  
Lattice Method ◽  
Coupled Method ◽  
Vortex Lattice Method ◽  
Finite Volume Approach ◽  
Euler Solver ◽  
Effective Wake ◽  
Total Velocity ◽  
Surface Vortex

A fully three-dimensional Euler solver, based on a finite volume approach, is developed and applied to the prediction of the unsteady effective wake for propellers subject to non-axisymmetric inflows. The Euler solver is coupled with an existing lifting-surface vortex-lattice method for the computation of unsteady propeller flows. The coupled method is validated against the uniform inflow case, in which ideally the uniform flow should be recovered as the effective wake. The predicted total velocity field correlates very well with that measured in the water tunnel experiment. Lastly, the unsteady effective wake predicted by the present method is compared with the steady effective wake predicted by the authors' previous steady method.

A Prescribed-Wake Vortex Lattice Method for Preliminary Design of Co-Axial, Dual-Rotor Wind Turbines

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Aaron Rosenberg ◽  
Anupam Sharma
Keyword(s):  
Wind Turbines ◽  
Vortex Lattice ◽  
Navier Stokes ◽  
Wake Vortex ◽  
Preliminary Design ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Trailing Vortices ◽  
Computational Fluid Dynamics Cfd ◽  
Reynolds Averaged Navier Stokes

This paper extends the prescribed-wake vortex lattice method (VLM) to perform aerodynamic analysis of dual-rotor wind turbines (DRWTs). A DRWT turbine consists of a large, primary rotor placed co-axially behind a smaller, secondary rotor. The additional vortex system introduced by the secondary rotor of a DRWT is modeled while taking into account the singularities that can occur when the trailing vortices from the secondary (upstream) rotor interact with the bound vortices of the main (downstream) rotor. Pseudo-steady assumption is invoked, and averaging over multiple relative rotor positions is performed to account for the primary and secondary rotors operating at different rotational velocities. The VLM solver is first validated against experiments and blade element momentum theory results for a conventional, single-rotor turbine. The solver is then verified for two DRWT designs against results from two computational fluid dynamics (CFD) methods: (1) Reynolds-averaged Navier–Stokes CFD with an actuator disk representation of the turbine rotors and (2) large-eddy simulations with an actuator line model. Radial distributions of sectional torque force and angle of attack show reasonable agreement between the three methods. Results of parametric sweeps performed using VLM agree qualitatively with the Reynolds-averaged Navier–Stokes (RANS) CFD results demonstrating that the proposed VLM can be used to guide preliminary design of DRWTs.

Thruster and Hull Interaction

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Ye Tian ◽  
Spyros A. Kinnas
Keyword(s):  
Experimental Data ◽  
Hybrid Method ◽  
Computational Efficiency ◽  
Vortex Lattice ◽  
Numerical Results ◽  
Navier Stokes ◽  
Dynamic Positioning ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Number Of Cells

A hybrid method which couples a vortex-lattice method (VLM) solver and a Reynolds-Averaged Navier–Stokes (RANS) solver is applied to simulate the interaction between a dynamic positioning (DP) thruster and a floating production storage and offloading (FPSO) hull. The hybrid method can significantly reduce the number of cells to fifth of that in a full-blown RANS simulation and thus greatly enhance the computational efficiency. The numerical results are first validated with available experimental data, and then used to assess the significance of the thruster/hull interaction in DP systems.

A Vortex Model of the Darrieus Turbine: An Analytical and Experimental Study

1979 ◽  
Vol 101 (4) ◽  
pp. 500-505 ◽  
Author(s):  
J. H. Strickland ◽  
B. T. Webster ◽  
T. Nguyen
Keyword(s):  
Experimental Study ◽  
Prediction Model ◽  
Vortex Lattice ◽  
Three Dimensional ◽  
Wake Flow ◽  
Two Dimensional ◽  
Lattice Method ◽  
Near Wake ◽  
Vortex Lattice Method ◽  
Vortex Model

An aerodynamic prediction model has been formulated for two- and three-dimensional Darrieus turbines using a vortex lattice method of analysis. Experiments were conducted on a series of two-dimensional rotor configurations in a water tow tank. The agreement between analysis and experiment was in general found to be good. This model should allow one to make accurate predictions of instantaneous aerodynamic blade forces and to characterize the near wake flow behind the rotor.

Aerodynamic Design and Test Result Analysis of a Three Stage Research Compressor

2004 ◽  
Author(s):  
Armel Touyeras ◽  
Michel Villain
Keyword(s):  
Cfd Simulation ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Aerodynamic Design ◽  
New Developments ◽  
Compressor Performance ◽  
Flow Effects ◽  
Stage Matching ◽  
Result Analysis ◽  
Test Result

The present paper describes the aerodynamic design and the test result analysis of a three-stage research compressor designed by Snecma Moteurs and tested at Ecole Centrale de Lyon, France. Firstly, the CREATE compressor, representative of the median or rear stages of modern high-pressure compressors, is presented. Particular emphasis is put on the CFD process employed in its design, which was based largely on three-dimensional Navier-Stokes multistage simulations. A brief description of the stage-by-stage matching achieved on the compressor is also presented. Test results available from traversal probes and laser velocimetry are compared with CFD simulation for overall compressor performance, stage-by-stage matching, and secondary flow effects. Prediction of the design and off-design compressor performance with 3D multistage tools is discussed. Finally, the prospects of new developments concerning the CFD tools and the evolution of the experimental compressor are also mentioned.

Feasibility Study of Incorporating Flow Unsteadiness in Control of Secondary Flows in Shrouded Turbines

2013 ◽  
Author(s):  
Jie Gao ◽  
Qun Zheng ◽  
Xiaoquan Jia
Keyword(s):  
High Pressure ◽  
Three Dimensional ◽  
Internal Flow ◽  
Secondary Flows ◽  
Navier Stokes ◽  
High Pressure Turbine ◽  
Numerical Investigations ◽  
Flow Interactions ◽  
Turbine Cascades ◽  
Flow Effects

The internal flow in turbomachinery is inherently unsteady, and the endwall losses are major sources of lost efficiency in high-pressure turbine cascades. Therefore, the investigation of the unsteady endwall flow interactions is valuable to improve the performance of high-pressure turbines. Unsteady and steady numerical investigations of endwall flow interactions of 1.5-stage shrouded turbines with straight and bowed vanes are performed using a three-dimensional Navier-Stokes viscous solver. Emphasis is placed on how unsteady stator-rotor interactions affect shrouded turbine endwall secondary flows, on the basis of which the feasibility of incorporating the unsteady endwall flow effects in the control of secondary flows is discussed in detail. Results from this investigation are well presented and discussed in this paper.

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