Selection of Implicit CFD Techniques for Unstructured Grids and Turbomachinery Applications

Pueblas, Jesús; Corral, Roque; Gisbert, Fernando

doi:10.2514/6.2013-2575

Cited by 3 publications

(1 citation statement)

References 11 publications

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“…In this analysis stage a steady time marched solution is enough, and the code can use either an explicit 4 stage Runge-Kutta or an inverse Euler implicit local time integration scheme. More details on the implicit integration scheme are given by Crespo et al (Crespo et al, 2015) and Pueblas et al (Pueblas et al, 2013). Several tools are available for the postprocessing of CFD solutions, in order to check the degree of fulfillment of the design criteria.…”

Section: Overview Of the Design Methodologymentioning

confidence: 99%

Automated 3D Aerodynamic Design Of Low Pressure Turbine Airfoils Using a Gpu Accelarated Adjoint Method

Puente

Corral²

2017

European Conference on Turbomachinery Fluid Dynamics and Hermodynamics

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A methodology for the full three dimensional automatic design of turbomachinery airfoils is presented, developed with the requirement of minimal output time. This requirement leads to the use of a gradient based algorithm, where derivatives are computed using the adjoint method. Where possible, the computational advantages of Graphics Processing Units have been used, qualitatively and quantitatively assessing the benefits of this approach. In order to illustrate the capabilities of the system, a Low Pressure Turbine vane has been redesigned, taking into consideration a set of rigorous design criteria. NOMENCLATURE ϕ Design variable δ Grid node displacement f Objective function h Helicity g Constraint function H Heaviside function I Augmented objective function R(ū) RANS equations residuals u Conservative variablesv Adjoint variables ADO Automatic Design Optimisation FLOP Floating point operations per second CPU Central Processing Unit GPU Graphics Processing Unit flop Floating point operations θ Angular polar coordinate

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Section: Overview Of the Design Methodologymentioning

confidence: 99%

Automated 3D Aerodynamic Design Of Low Pressure Turbine Airfoils Using a Gpu Accelarated Adjoint Method

Puente

Corral²

2017

European Conference on Turbomachinery Fluid Dynamics and Hermodynamics

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An Implicit Harmonic Balance Method in Graphics Processing Units for Oscillating Blades

Crespo

Corral

Pueblas

2015

Journal of Turbomachinery

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An implicit harmonic balance (HB) method for modeling the unsteady nonlinear periodic flow about vibrating airfoils in turbomachinery is presented. An implicit edge-based three-dimensional Reynolds-averaged Navier–Stokes equations (RANS) solver for unstructured grids, which runs both on central processing units (CPUs) and graphics processing units (GPUs), is used. The HB method performs a spectral discretization of the time derivatives and marches in pseudotime, a new system of equations where the unknowns are the variables at different time samples. The application of the method to vibrating airfoils is discussed. It is shown that a time-spectral scheme may achieve the same temporal accuracy at a much lower computational cost than a backward finite-difference method at the expense of using more memory. The performance of the implicit solver has been assessed with several application examples. A speed-up factor of 10 is obtained between the spectral and finite-difference version of the code, whereas an additional speed-up factor of 10 is obtained when the code is ported to GPUs, totalizing a speed factor of 100. The performance of the solver in GPUs has been assessed using the tenth standard aeroelastic configuration and a transonic compressor.

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Study of the Effect of the Scatter of Acoustic Modes on Turbine Flutter

Gallardo¹,

Sotillo²,

Bermejo³

2019

Journal of Turbomachinery

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The prediction of aerodynamic damping is a relevant issue for turbomachinery design trends. Most of the conventional analysis methodologies for the study of aeroelastic forcing in use until recently neglect any hypothetical effects of adjacent rows. However, in recent years, it has become unquestionable that acoustic waves and nearly convected perturbations reflected in neighboring rows play a significant role in the evaluation of the overall unsteady loading of the blades. In this paper, a study of the impact of these effects in flutter stability margin is performed. For this analysis, ITP Aero’s in-house unsteady 3D frequency domain linearized RANS solver is used. The subject of this research is a setup which is a close representation of a proper LPT geometry. The influence of neighboring rows is examined, taking into consideration how the interactions between rows are scattered into several circumferential modes, as well as into radial modes. A quantitative assessment of all these effects is performed to understand the relative relevance of each one of them, and the results of unsteady aerodynamic blade loading are compared with those of a single-row simulation.

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Selection of Implicit CFD Techniques for Unstructured Grids and Turbomachinery Applications

Cited by 3 publications

References 11 publications

Automated 3D Aerodynamic Design Of Low Pressure Turbine Airfoils Using a Gpu Accelarated Adjoint Method

Automated 3D Aerodynamic Design Of Low Pressure Turbine Airfoils Using a Gpu Accelarated Adjoint Method

An Implicit Harmonic Balance Method in Graphics Processing Units for Oscillating Blades

Study of the Effect of the Scatter of Acoustic Modes on Turbine Flutter

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