scholarly journals A Two-Temperature Open-Source CFD Model for Hypersonic Reacting Flows, Part One: Zero-Dimensional Analysis

Aerospace ◽  
2016 ◽  
Vol 3 (4) ◽  
pp. 34 ◽  
Author(s):  
Vincent Casseau ◽  
Rodrigo Palharini ◽  
Thomas Scanlon ◽  
Richard Brown
Keyword(s):  
Open Source ◽  
Dimensional Analysis ◽  
Reacting Flows ◽  
Cfd Model ◽  
Two Temperature

scholarly journals A Two-Temperature Open-Source CFD Model for Hypersonic Reacting Flows, Part Two: Multi-Dimensional Analysis

Aerospace ◽  
2016 ◽  
Vol 3 (4) ◽  
pp. 45 ◽  
Author(s):  
Vincent Casseau ◽  
Daniel Espinoza ◽  
Thomas Scanlon ◽  
Richard Brown
Keyword(s):  
Open Source ◽  
Dimensional Analysis ◽  
Reacting Flows ◽  
Cfd Model ◽  
Two Temperature

scholarly journals In-House, Open-Source 3D-Software-Based, CAD/CAM-Planned Mandibular Reconstructions in 20 Consecutive Free Fibula Flap Cases: An Explorative Cross-Sectional Study With Three-Dimensional Performance Analysis

2021 ◽  
Vol 11 ◽  
Author(s):  
Lucas M. Ritschl ◽  
Paul Kilbertus ◽  
Florian D. Grill ◽  
Matthias Schwarz ◽  
Jochen Weitz ◽  
...  
Keyword(s):  
Open Source ◽  
Dimensional Analysis ◽  
Open Source Software ◽  
Three Dimensional ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Free Fibula Flap ◽  
Cross Sectional ◽  
Cad Cam ◽  
Free Fibula

BackgroundMandibular reconstruction is conventionally performed freehand, CAD/CAM-assisted, or by using partially adjustable resection aids. CAD/CAM-assisted reconstructions are usually done in cooperation with osteosynthesis manufacturers, which entails additional costs and longer lead time. The purpose of this study is to analyze an in-house, open-source software-based solution for virtual planning.Methods and MaterialsAll consecutive cases between January 2019 and April 2021 that underwent in-house, software-based (Blender) mandibular reconstruction with a free fibula flap (FFF) were included in this cross-sectional study. The pre- and postoperative Digital Imaging and Com munications in Medicine (DICOM) data were converted to standard tessellation language (STL) files. In addition to documenting general information (sex, age, indication for surgery, extent of resection, number of segments, duration of surgery, and ischemia time), conventional measurements and three-dimensional analysis methods (root mean square error [RMSE], mean surface distance [MSD], and Hausdorff distance [HD]) were used.ResultsTwenty consecutive cases were enrolled. Three-dimensional analysis of preoperative and virtually planned neomandibula models was associated with a median RMSE of 1.4 (0.4–7.2), MSD of 0.3 (-0.1–2.9), and HD of 0.7 (0.1–3.1). Three-dimensional comparison of preoperative and postoperative models showed a median RMSE of 2.2 (1.5–11.1), MSD of 0.5 (-0.6–6.1), and HD of 1.5 (1.1–6.5) and the differences were significantly different for RMSE (p < 0.001) and HD (p < 0.001). The difference was not significantly different for MSD (p = 0.554). Three-dimensional analysis of virtual and postoperative models had a median RMSE of 2.3 (1.3–10.7), MSD of -0.1 (-1.0–5.6), and HD of 1.7 (0.1–5.9).ConclusionsOpen-source software-based in-house planning is a feasible, inexpensive, and fast method that enables accurate reconstructions. Additionally, it is excellent for teaching purposes.

Hydrodynamic Coupling of Viscous and Non-Viscous Numerical Wave Solutions Within the Open-Source Hydrodynamics Framework REEF3D

2021 ◽  
Author(s):  
Weizhi Wang ◽  
Csaba Pákozdi ◽  
Arun Kamath ◽  
Tobias Martin ◽  
Hans Bihs
Keyword(s):  
High Resolution ◽  
Boundary Conditions ◽  
Open Source ◽  
Laplace Equation ◽  
Scale Model ◽  
Surface Boundary ◽  
Cfd Model ◽  
Hydrodynamic Coupling ◽  
Coupling Strategy ◽  
Numerical Wave

Abstract A comprehensive understanding of the marine environment in the offshore area requires phase-resolved wave information. For the far-field wave propagation, computational efficiency is crucial, as large spatial and temporal scales are involved. For the near-field extreme wave events and wave impacts, high resolution is required to resolve the flow details and turbulence. The combined use of a computationally efficient large-scale model and a high-resolution local-scale solver provides a solution the combines accuracy and efficiency. This article introduces a coupling strategy between the efficient fully nonlinear potential flow (FNPF) solver REEF3D::FNPF and the high-fidelity computational fluid dynamics (CFD) model REEF3D::CFD within in the open-source hydrodynamics framework REEF3D. REEF3D::FNPF solves the Laplace equation together with the boundary conditions on a sigma-coordinate. The free surface boundary conditions are discretised using high-order finite difference methods. The Laplace equation for the velocity potential is solved with a conjugated gradient solver preconditioned with geometric multi-grid provided by the open-source library hypre. The model is fully parallelised following the domain decomposition strategy and the MPI protocol. The waves calculated with the FNPF solver are used as wave generation boundary condition for the CFD based numerical wave tank REEF3D::CFD. The CFD model employs an interface capturing two-phase flow approach that can resolve complex wave structure interaction, including breaking wave kinematics and turbulent effects. The presented hydrodynamic coupling strategy is tested for various wave conditions and the accuracy is fully assessed.

A CFD Model for Reacting Flows in an Aero-Engine Hot End Simulator

2005 ◽  
Author(s):  
L. Ma ◽  
M. C. Pourkashanian ◽  
C. W. Wilson
Keyword(s):  
Boundary Conditions ◽  
Three Dimensional ◽  
Chemical Species ◽  
Aircraft Engine ◽  
Reacting Flows ◽  
Cfd Model ◽  
Operational Conditions ◽  
Aero Engine ◽  
Aircraft Wake ◽  
Conversion Efficiencies

This paper presents a three-dimensional CFD model that numerically simulates the physical and chemical species transformations in the aero-engine turbine and nozzle aimed at contributing to an improved understanding of the minor species emitted by the aircraft, in particular the production of the gaseous aerosol precursors such as SO3, H2SO4 and HONO within the aircraft engine. The results presented are for the model applications to an aero-engine Hot End Simulator (HES). The HES was designed in the PARTEMIS programme to recreate the thermodynamic profile in the turbine and nozzle through which the hot gases pass after leaving the combustor so that detailed measurements can be made within the HES providing key boundary conditions and validations to the CFD model predictions. A detailed sulphur reaction mechanism has been incorporated in the numerical model, together with hydrocarbon-air and nitrogen chemistry, so that the effect of both engine condition and fuel sulphur content on the sulphur IV to VI conversion, as well as NOx/NOy conversion, in the post combustor region can be numerically predicted. For the two operational conditions studied, it is noted that there is still a significant portion of sulphur conversions taking place within the HES, although they are smaller when compared with the sulphur conversions that take place in the combustor. Overall conversion efficiencies of about 3.2% and 2.8% have been predicted for the Cruise and the Modern conditions studied, respectively, of which 0.6% and 0.7% were predicted occurring within the HES, respectively. The CFD predictions compared well with the available data from the HES measurements, although considerable uncertainties in the model input exist. The modelling results suggest that reasonable predictions can be obtained for the fluid flow, heat transfer and the chemical species transformations that occur in the turbine and nozzle, particularly for some of the unstable species that are not readily obtained through measurements. These results could also provide useful information/boundary conditions for the subsequent post engine modelling of the new particulate materials formed within the aircraft wake.

New two-temperature dissociation model for reacting flows

10.2514/3.478 ◽  
1993 ◽  
Vol 7 (4) ◽  
pp. 687-696 ◽  
Author(s):  
David P. Olynick ◽  
H. A. Hassan
Keyword(s):  
Reacting Flows ◽  
Dissociation Model ◽  
Two Temperature
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