Robust Surface Evolution and Mesh Deformation for Three Dimensional Aircraft Icing Applications on a Swept GLC-305 Airfoil
16 Jun 2014-
TL;DR: In this article, a mesh generation strategy for problems involving deforming geometries produced by three-dimensional ice accretion simulations, which are more challenging than corresponding two-dimensional problems, is presented.
Abstract: This paper presents the application of a mesh generation strategy for problems involving deforming geometries produced by three-dimensional ice accretion simulations, which are more challenging than corresponding two-dimensional problems. A technique to deform a discrete surface as it evolves due to the accretion of ice is described. The surface evolution algorithm is based on a face-offseting approach. A fast algebraic technique to propagate the computed surface deformations into the surrounding volume mesh while maintaining geometric mesh quality is also presented. Results are presented for a complex glaze ice on a rectangular planform wing with a constant GLC-305 airfoil section and rime ice and glaze shapes on a swept, tapered GLC-305 wing also with a GLC-305 cross section.
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TL;DR: In this paper, a mesh generation strategy that facilitates the numerical simulation of ice accretion on realistic aircraft configurations by automating the deformation of surface and volume meshes in response to the evolving ice shape is presented.
Abstract: This paper presents a mesh generation strategy that facilitates the numerical simulation of ice accretion on realistic aircraft configurations by automating the deformation of surface and volume meshes in response to the evolving ice shape. The discrete surface evolution algorithm is based on a face-offsetting strategy that uses an eigenvalue decomposition to determine 1) the nodal offset direction and 2) a null space in which the quality of the surface mesh is improved via point redistribution. A fast algebraic technique is then used to propagate the computed surface deformations into the surrounding volume mesh. Due to inherent limitations in the icing model employed here, there is no intent to present a tool to predict three-dimensional ice accretions but, instead, to demonstrate a meshing strategy for surface evolution and mesh deformation that is appropriate for aircraft icing applications. In this context, sample results are presented for a complex glaze-ice accretion on a rectangular-planform wing ...
14 citations
TL;DR: The computational results show that the GCB greedy algorithm is able to remarkably promote the efficiency of computing the interpolation errors in the data reducing procedure by dozens of times and tends to generate a more significant efficiency improvement for mesh deformation when a larger-scale mesh is applied.
8 citations
Cites background from "Robust Surface Evolution and Mesh D..."
...Introduction The essential issue for aerodynamic shape optimizations[1–4], aircraft icing simulations[5, 6] and aeroelasticity predictions[7–10] is to allow the computational mesh deformed so as to facilitate reproductions of aerodynamic effects induced by shape shifting....
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TL;DR: In this article, an efficient multiple point selection method has been developed based on the conventional Greedy method, where multiple points with maximum local error are selected simultaneously into the support set, with which an interpolation model is finally built to compute the displacements of the volume mesh nodes.
7 citations
13 Jun 2016
TL;DR: In this article, the authors present results from the latest LEWICE release, version 3.5, which differs from previous releases in its ability to model mixed phase and ice crystal conditions such as those encountered inside an engine.
Abstract: A research project is underway at NASA Glenn to produce computer software that can accurately predict ice growth under any meteorological conditions for any aircraft surface. This report will present results from the latest LEWICE release, version 3.5. This program differs from previous releases in its ability to model mixed phase and ice crystal conditions such as those encountered inside an engine. It also has expanded capability to use structured grids and a new capability to use results from unstructured grid flow solvers. A quantitative comparison of the results against a database of ice shapes that have been generated in the NASA Glenn Icing Research Tunnel (IRT) has also been performed. This paper will extend the comparison of ice shapes between LEWICE 3.5 and experimental data from a previous paper. Comparisons of lift and drag are made between experimentally collected data from experimentally obtained ice shapes and simulated (CFD) data on simulated (LEWICE) ice shapes. Comparisons are also made between experimentally collected and simulated performance data on select experimental ice shapes to ensure the CFD solver, FUN3D, is valid within the flight regime. The results show that the predicted results are within the accuracy limits of the experimental data for the majority of cases.
5 citations
Dissertation•
12 Dec 2018
TL;DR: This thesis presents the results obtained with different CFD methods : the Arbitrary Lagrangian Eulerian (ALE) flow solvers with explicit and implicit schemes are presented and coupled to the moving mesh process, the feature-based unsteady mesh adaptation for moving geometries takes into account the changes of connectivites during the whole simulation.
Abstract: When dealing with CFD problems, mesh adaptation is interesting for its ability to approach the asymptotic convergence and to obtain an accurate prediction for complex flows at a lower cost. Anisotropic mesh adaptation method reduces the number of degrees of freedom required to reach a given solution accuracy, thus impact favorably the CPU time. Moreover, it reduces the numerical scheme dissipation by automatically taking into account the anisotropy of the physical phenomena inside the mesh. Two main approaches exist in the literature. Feature-based mesh adaptation which is mainly deduced from an interpolation error estimate using the Hessian of the chosen sensor controls the interpolation error of the sensor over the whole computational domain. Such approach is easy to set-up and has a wide range of application, but it does not take into account the considered PDE used to solve the problem. On the other hand, goal-oriented mesh adaptation, which focuses on a scalar output function, takes into consideration both the solution and the PDE in the error estimation thanks to the adjoint state. But, the design of such error estimate is much more complicated. This thesis presents the results obtained with different CFD methods : the Arbitrary Lagrangian Eulerian (ALE) flow solvers with explicit and implicit schemes are presented and coupled to the moving mesh process, the feature-based unsteady mesh adaptation for moving geometries takes into account the changes of connectivites during the whole simulation, the adjoint state is extended to moving geometries problems and goal-oriented unsteady mesh adaptation for moving meshes is derived from an a priori error estimate. Several numerical examples are considered in the aeronautics sector and the field of civil security.
5 citations
References
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TL;DR: In this paper, two new two-equation eddy-viscosity turbulence models are presented, which combine different elements of existing models that are considered superior to their alternatives.
Abstract: Two new two-equation eddy-viscosity turbulence models will be presented. They combine different elements of existing models that are considered superior to their alternatives. The first model, referred to as the baseline (BSL) model, utilizes the original k-ω model of Wilcox in the inner region of the boundary layer and switches to the standard k-e model in the outer region and in free shear flows. It has a performance similar to the Wilcox model, but avoids that model's strong freestream sensitivity
15,459 citations
TL;DR: A new mesh movement algorithm for unstructured grids is developed which is based on interpolating displacements of the boundary nodes to the whole mesh with radial basis functions (RBF's), which can handle large mesh deformations caused by translations, rotations and deformations.
648 citations
TL;DR: In this paper, a complete analysis of the temperature of an unheated surface in icing conditions is presented for the several significant regimes (i.e., less than 32°F, at 32° F, and above 32 °F) as a function of air speed, altitude, ambient temperature, and liquid water content.
Abstract: The thermal analysis of a heated surface in icing conditions has been extensively treated in the literature. Except for the work of Tribus, however, little has been done on the analysis of an unheated icing surface. This latter analysis is significant in the design of cyclic thermal deicing systems that are attractive for small high-speed aircraft for which thermal anti-icing requirements have become severe. In this paper, a complete analysis of the temperature of an unheated surface in icing conditions is presented for the several significant regimes (i.e., less than 32°F., at 32°F., and above 32°F.) as a function of air speed, altitude, ambient temperature, and liquid water content. The results are presented in graphical form and permit the rapid determination of surface temperature for a wide range of variables. Curves are presented to determine the speeds beyond which no ice accretion will occur. Curves are also presented to indicate the surface temperature and the rate of ice sublimation which takes place when an ice-covered surface emerges into clear air. One significant result of this study is the introduction of a new basic variable referred to as the "freezing-fraction," which denotes the proportion of the impinging liquid which freezes in the impingement region. The fact that some of the liquid does not freeze in the impingement region tends to explain the observed variation in ice formation shape with temperature, speed, and water catch. New test data obtained at Mt. Washington, N.H., for stagnation-point surface temperatures of an unheated plastic cylinder in natural and artificial icing conditions are included in the Appendix. These data substantiate the validity of the assumptions made in the theoretical analysis.
573 citations
TL;DR: A novel mesh deformation algorithm for unstructured polyhedral meshes is developed utilizing a tree-code optimization of a simple direct interpolation method, shown to provide mesh quality that is competitive with radial basis function based methods, with markedly better performance in preserving boundary layer orthogonality in viscous meshes.
196 citations
01 Jan 1999
TL;DR: A semi-empirical approach was used to incorporate first order physical effects of large droplet phenomena into icing software, and predicted results show that the predicted results are within the accuracy limits of the experimental data for the majority of cases.
Abstract: A research project is underway at NASA Lewis to produce a computer code which can accurately predict ice growth under any meteorological conditions for any aircraft surface. This report will present results from version 2.0 of this code, which is called LEWICE. This version differs from previous releases due to its robustness and its ability to reproduce results accurately for different spacing and time step criteria across computing platform. It also differs in the extensive amount of effort undertaken to compare the results in a quantified manner against the database of ice shapes which have been generated in the NASA Lewis Icing Research Tunnel (IRT). The results of the shape comparisons are analyzed to determine the range of meteorological conditions under which LEWICE 2.0 is within the experimental repeatability. This comparison shows that the average variation of LEWICE 2.0 from the experimental data is 7.2% while the overall variability of the experimental data is 2.5%.
137 citations