Newmerical Technologies International

Montréal, Canada

Newmerical Technologies International

Montréal, Canada
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Croce G.,University of Udine | De Candido E.,University of Udine | Habashi W.G.,McGill University | Munzar J.,McGill University | And 4 more authors.
Journal of Aircraft | Year: 2010

Ice roughness, which has a major influence on in-flight icing heat transfer and, hence, ice shapes, is generally input from empirical correlations to numerical simulations. It is given as uniform in space, while sometimes being varied in time. In this paper, a predictive model for roughness evolution in both space and time during in-flight icing is presented. The distribution is determined mathematically via a Lagrangian model that accounts for the stochastic process of bead nucleation, growth, and coalescence into moving droplets and/or rivulets and/or water film. This general model matches well the spatial and temporal roughness distributions observed in icing tunnel experiments and is embedded in FENSAP-ICE, extending its applicability outside the range of airfoil types for which correlations exist. Thus, an additional important step has been taken toward removing another empirical aspect of in-flight icing simulation. Copyright © 2010 by W.G. Habashi.

Fossati M.,McGill University | Habashi W.G.,McGill University | Habashi W.G.,Bombardier | Baruzzi G.S.,Newmerical Technologies International
Journal of Aircraft | Year: 2012

The computational cost of viscous turbulent aeroicing simulations is a limitation that needs to be addressed more extensively using computational fluid dynamics (CFD) for aircraft in-flight icing certification. To overcome this computational burden, a reduced-order modeling (ROM) approach, based on proper orthogonal decomposition and kriging interpolation techniques, is applied to the computation of the water impact pattern of supercooled large droplets on aircraft. Relying on an appropriate database of high-fidelity, full-order simulations, theROMapproach provides an accurate lower-order approximation of the system in terms of a linear combination of appropriate functions. The resulting surrogate solution is successfully compared with experimental and CFD results for twodimensional and three-dimensional cases, including a complete aircraft case. © 2011 by Wagdi Habashi.

Aube M.S.,Newmerical Technologies International | Habashi W.G.,Newmerical Technologies International | Habashi W.G.,McGill University | Wang H.,Newmerical Technologies International | Torok D.,Newmerical Technologies International
International Journal for Numerical Methods in Fluids | Year: 2010

This paper addresses the critical issue of the accuracy of CFD predictions for wind engineering. Flows around the Silsoe Cube, a high-rise building (the Jin Mao Tower), and a low-rise large-span building (the Pudong International Airport) are computed with the Navier-Stokes solver FENSAP and compared with measurements. Computations are carried out for two wind directions, by solving the steady-state ensemble-averaged Navier-Stokes equations with the Spalart-Allmaras one-equation turbulence model. Pressure coefficients compare well with wind tunnel experiments and the accuracy of the flow solutions is further improved via an automatic mesh adaptation that dynamically places grid points where the flow physics require them, while keeping the number of unknowns and solution time substantially at the same level. Copyright © 2009 John Wiley & Sons, Ltd.

Reid T.,Newmerical Technologies International | Baruzzi G.S.,Newmerical Technologies International | Habashi W.G.,McGill University | Habashi W.G.,CFD Laboratory
Journal of Aircraft | Year: 2012

This paper presents a truly unsteady approach for the numerical simulation of in-flight electrothermal anti-icing or de-icing, using a conjugate heat transfer technique. This numerical approach has been implemented in FENSAPICE to compute the complex heat transfer phenomena occurring during in-flight de-icing with multiple heating elements following independent cycling. At each time step, the energy fluxes through the aircraft's solid skin, the melting ice layer, the liquid water film, and the external fluid are computed. The ice shape is then modified by taking into account the opposing mass balance effects of ice accreting due to the impact of supercooled droplets and/or water runback, and the partial or total melting of the existing ice layer due to heating. The results of the verification of this phase-change conduction code are presented, followed by a study of intercycle de-icing on a wing, showing intercycle ice growth. Copyright © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

Switchenko D.,McGill University | Habashi W.G.,McGill University | Baruzzi G.,Newmerical Technologies International | Ozcer I.,Newmerical Technologies International
32nd ASME Wind Energy Symposium | Year: 2014

A numerical simulation of a complex wind turbine icing event is performed using the FENSAP-ICE™ simulation system. First, 2D and 3D simulations of a characteristic atmospheric icing event on a small wind turbine are compared to experimental data. Comparable results are obtained with both methods, supporting the use of the 2D blade section approach for more computationally intensive simulations, which would be prohibitively expensive in 3D. A complex, historical weather event is then simulated on an industrial-scale wind turbine. The selected weather event is 17 hours long and based on data collected at a wind farm in the Gaspé Peninsula, Québec, Canada. Since the actual turbine geometry was not available, the WindPACT 1.5 MW wind turbine rotor was selected for use in the simulations as it is of comparable size and rating to the wind turbines located on the Gaspé site. The performance simulation of the contaminated turbine compares well to the characteristics of the actual contaminated turbines at the Gaspé wind farm.

Abdollahi V.,McGill University | Habashi W.G.,McGill University | Fossati M.,McGill University | Baruzzi G.S.,Newmerical Technologies International
5th AIAA Atmospheric and Space Environments Conference | Year: 2013

A fine-scale model of Supercooled Large Droplets dynamics is proposed based on a quasi-molecular approach, a meso-scale method that mimics the interaction between quasimolecules within a single liquid droplet. Each quasi-molecule is a combination of a large number of real molecules which are considered to be an ensemble. The goal is to simulate the deformation and the splashing processes of a droplet to obtain a better understanding of the dynamics of large droplets collisions with aircraft at realistic flight conditions in order to refine the macroscopic Eulerian description of the process.

Veillard X.,McGill University | Veillard X.,Imperial College London | Habashi W.G.,McGill University | Habashi W.G.,CFD Laboratory | Baruzzi G.S.,Newmerical Technologies International
Journal of Propulsion and Power | Year: 2011

The present paper develops the particular methodology required to simulate icing not only on the front of a jet engine, but inside multistage ones, to respond to recent safety and performance concerns. When flying in certain weather conditions, engines have been found to ingest a mix of iced and liquid particles that can result in a dangerous buildup onthe internal components of the compressor. The ice can then shed and may cause mechanical damage and performance losses to downstream components. To cost-effectively replicate such an environment, a threedimensional quasi-steady numerical approach is developed to model both rotating and static components and their interaction. An intercomponent mixing-plane approach, along with stagnation and radial equilibrium boundary conditions, has been implemented, allowing the treatment of multistage unequal-pitch blade rows via afinite element interpolation method and proper circumferential averaging. The approach is first validated for the well-documented Aachen turbine, and then used on a NASA compressor stage to highlight impingement locations of supercooled droplets and the corresponding ice shapes. Copyright © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

Bakkar A.,McGill University | Habashi W.G.,McGill University | Fossati M.,McGill University | Baruzzi G.S.,Newmerical Technologies International
Computers and Fluids | Year: 2015

A stabilized finite element formulation of the level set equation is proposed for the numerical simulation of water droplet dynamics for in-flight ice accretion problems. The variational multi-scale and Taylor-Galerkin approaches are coupled such that the temporal derivative in the weak Galerkin formulation is replaced with a Taylor series expansion improving the temporal accuracy of the scheme. The variational multi-scale approach is then applied to the semi-discrete equation, allowing the stabilization terms to appear naturally. Taylor series expansions up to the fourth order have been studied in terms of accuracy and convergence rates. A second order implicit expansion was found to provide a good trade-off between accuracy and computational cost when compared to a fourth order implicit expansion. Validation is done through a number of benchmark cases considering droplet stretching and high-speed advection. Results indicate good mass conservation characteristics compared to other methods available in the literature. © 2015 Elsevier Ltd.

Aliaga C.N.,Newmerical Technologies International | Aliaga C.N.,CFD Laboratory | Aube M.S.,Newmerical Technologies International | Aube M.S.,CFD Laboratory | And 4 more authors.
Journal of Aircraft | Year: 2011

In-flight ice accretion, even though driven by a steady flow airstream, is an inherently unsteady phenomenon. It is, however, completely ignored in icing simulation codes (one-shot) or, at best approximated via quasi-steady modeling (multishot). The final ice shapes thus depend on the length of the total accretion time (one-shot), or of the arbitrarily prescribed time intervals (multishot), during which the impact of ice growth on both airflow and water impingement is ignored. Such a longstanding heuristic approximation is removed in this paper by coupling in time the dilute two-phase flow (air and water droplets flow) with ice accretion, and is implemented in a new code, FENSAP-ICE-Unsteady. The two-phase flow is solved using the coupled Navier-Stokes and water concentration equations, and the water film characteristics and ice shapes are obtained from laws of conservation of mass and energy within the thin film layer. To continually update the geometry of the iced surface in time, arbitrary Lagrangian-Eulerian terms are added to all governing equations to account for mesh movement in the case of stationary components. In the case of rotating/stationary interacting components, a dynamically stitched grid is used. The numerical results clearly show that unsteady modeling improves the accuracy of both rime and glaze ice shape prediction, compared with the traditional quasi-steady approach with frozen solutions. The unsteady model is shown to open the door for a unified approach to icing on fixed wings, on helicopters with blades/rotors/fuselage systems. Problems of current concern in the icing community such as the ingestion of ice crystals at high altitude become tractable with the new formulation. Copyright © 2010 by W.G. Habashi.

Bilodeau D.R.,McGill University | Bilodeau D.R.,CFD Laboratory | Habashi W.G.,McGill University | Habashi W.G.,CFD Laboratory | And 3 more authors.
Journal of Aircraft | Year: 2015

A conservative Eulerian numerical approach for modeling postimpact Supercooled Large Droplets undergoing splashing and bouncing on aircraft surfaces is presented. The approach introduces the effect of the postimpact droplets by successive solutions of the conservation equations. Two models have been selected to identify the droplet splashing and bouncing conditions, and to provide initial conditions for the reinjected water. The method has been applied to droplet impingement in Supercooled Large Droplet conditions on clean and iced NACA 23012 geometries, as well as the MS(1)-0317 airfoil, and the results have been compared to experimental data. Good agreement is observed for both impingement limits and collection efficiency. Additionally, the method has been applied to a threeelement high-lift configuration operating in one of the proposed Appendix O Supercooled Large Droplet environments to demonstrate the danger posed by the re-impingement of splashing and bouncing droplets on complex interacting aerodynamic components. © 2014 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

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