Computational Fluid Mechanics

A one-equation turbulence model based on the turbulent kinetic energy equation is presented. The model is motivated by the success of the Johnson-King model and incorporates a number of features uncovered by Simpson's experiments on separated flows. Based on the results obtained, the model duplicates the success of algebraic models in attached flow regions and outperforms the two-equation models in detached flow regions

Computational fluid mechanics

Two papers are included in this progress report. In the first, the compressible Navier-Stokes equations have been used to compute leading edge receptivity of boundary layers over parabolic cylinders. Natural receptivity at the leading edge was simulated and Tollmien-Schlichting waves were observed to develop in response to an acoustic disturbance, applied through the farfield boundary conditions. To facilitate comparison with previous work, all computations were carried out at a free stream Mach number of 0.3. The spatial and temporal behavior of the flowfields are calculated through the use of finite volume algorithms and Runge-Kutta integration. The results are dominated by strong decay of the Tollmien-Schlichting wave due to the presence of the mean flow favorable pressure gradient. The effects of numerical dissipation, forcing frequency, and nose radius are studied. The Strouhal number is shown to have the greatest effect on the unsteady results. In the second paper, a transition model for low-speed flows, previously developed by Young et al., which incorporates first-mode (Tollmien-Schlichting) disturbance information from linear stability theory has been extended to high-speed flow by incorporating the effects of second mode disturbances. The transition model is incorporated into a Reynolds-averaged Navier-Stokes solver with a one-equation turbulence model. Results using a variable turbulent Prandtl number approach demonstrate that the current model accurately reproduces available experimental data for first and second-mode dominated transitional flows. The performance of the present model shows significant improvement over previous transition modeling attempts

Computational fluid mechanics utilizing the variational principle of modeling damping seals

An analysis for modeling damping seals for use in Space Shuttle main engine turbomachinery is being produced. Development of a computational fluid mechanics code for turbulent, incompressible flow is required

Internal computational fluid mechanics on supercomputers for aerospace propulsion systems

The accurate calculation of three-dimensional internal flowfields for application towards aerospace propulsion systems requires computational resources available only on supercomputers. A survey is presented of three-dimensional calculations of hypersonic, transonic, and subsonic internal flowfields conducted at the Lewis Research Center. A steady state Parabolized Navier-Stokes (PNS) solution of flow in a Mach 5.0, mixed compression inlet, a Navier-Stokes solution of flow in the vicinity of a terminal shock, and a PNS solution of flow in a diffusing S-bend with vortex generators are presented and discussed. All of these calculations were performed on either the NAS Cray-2 or the Lewis Research Center Cray XMP

Workshops for Learning in Computational Fluid Mechanics

The must-do of teaching Computational Fluid Dynamics (CFD) is the practical component. The main aim of the present paper is to propose test cases used in research. When these benchmarks are conveniently scaled-down and parameterized, students improve their understanding of the strong and weak points of the numerical models and gain an insight into the fluid dynamics processes learnt in the classroom. The goal is to prepare students who are new in this area to become self-sufficient in engineering practice.Comunicación del proyecto PID1415_030 presentada en la Second International Conference on Technological Ecosystem for Enhancing Multiculturality (TEEM'14

Computational fluid mechanics utilizing the variational principle of modeling damping seals

A computational fluid dynamics code for application to traditional incompressible flow problems has been developed. The method is actually a slight compressibility approach which takes advantage of the bulk modulus and finite sound speed of all real fluids. The finite element numerical analog uses a dynamic differencing scheme based, in part, on a variational principle for computational fluid dynamics. The code was developed in order to study the feasibility of damping seals for high speed turbomachinery. Preliminary seal analyses have been performed

Study of alternative geometries for fluidic oscillators by means of computational fluid mechanics

Se estudiará el fllujo en el interior de osciladores fluídicos mediante el uso de un código comercial de Mecánica de Fluidos Computacional.Se estudiarán diferentes diseños y se compararán sus rendimientos.1. Documentación y estudio del estado del arte. 2. Aprendizaje de los conceptos básicos de la Mecánica de Fluidos Computacional. 3. Aprendizaje de los programas ICEM CFD y ANSYS-FLUENT. 4. Selección de las geometrías y parámetros a estudiar.5. Mallado de dichas geometrías mediante ICEM CFD. 5. Simulación mediante ANSYS-FLUENT. 7. Extracción y análisis de resultados. 8. Conclusiones

A note on symmetry boundary conditions in finite element methods

AbstractA short discussion on two kinds of symmetry boundary conditions in the context of variational formulations and finite element methods is presented. Applications including modeling of open boundaries in computational fluid mechanics are discussed and a numerical example is presented

Численная гидродинамическая модель атмосферной дисперсии загрязнений вокруг зданий

The computational fluid mechanics model of is atmospheric dispersion in the vicinity of buildings is developed. The validation of model against field experiment was performed. The application of model to problem of estimation of concentration near contaminated buildings located at the territory of Pridneprovsky Chemical Plant is presented