Compressible Flow Research Papers - Academia.edu (original) (raw)

In this study, turbulent compressible gas flow in a rectangular micro-channel is numerically investigated. The gas flow assumed to be in the subsonic regime up to Mach number about 0.7. Five low and high Reynolds number RANS turbulence... more

In this study, turbulent compressible gas flow in a rectangular micro-channel is numerically investigated. The gas flow assumed to be in the subsonic regime up to Mach number about 0.7. Five low and high Reynolds number RANS turbulence models are used for modeling the turbulent flow. Two types of mesh are generated depending on the employed turbulence model. The computations are performed for Reynolds number up to 19000 and two inlet pressures of 1102 kPa and 499 kPa. The longitudinal variations of flow characteristics such as pressure, temperature, Mach number and friction factor are investigated. The experimental data are also used for the sake of comparison and to find which turbulence model has the best performance. The results show that the turbulence models with wall functions have generally better agreement with the experimental data than those one without wall function. The numerical results are different for normal size pipe flow.

Abstract : This report describes the research effort which was undertaken to extend the capability of numerical techniques developed for computing Magnus effects over right circular cones to artillery projectile shapes of interest to the... more

Abstract : This report describes the research effort which was undertaken to extend the capability of numerical techniques developed for computing Magnus effects over right circular cones to artillery projectile shapes of interest to the Army. The changes involved: (1) introduction of longitudinal pressure gradient effects in the boundary layer equations; (2) introduction of turbulent transport properties into the boundary layer equations; (3) modification of the inviscid flow computation for a more general body configuration; and (4) modification of the technique for computing the three dimensional displacement surface. (Author)

Basing on the static energy criterion for a bounded domain of an arbitrary shape and with regard for the boundary conditions at all parts of the boundary, the stability of a two-layer system of inhomogeneous barotropic fluids in the... more

Basing on the static energy criterion for a bounded domain of an arbitrary shape and with regard for the boundary conditions at all parts of the boundary, the stability of a two-layer system of inhomogeneous barotropic fluids in the uniform gravity field is studied for arbitrary distributions of their densities and elastic properties over depth. Almost coinciding with each other (up to the strictness of one of the two inequalities), equally valid for an arbitrary number of layers, the necessary and sufficient conditions for stability are obtained, that represents a new exhaustive result for the problem considered. Additionally (with compressibility admitted) possible influence of viscosity (which may be anisotropic), and also the case when the layers consist of solid elastic materials, are considered. In the case of instability, the lower estimates for the greatest rate of disturbances growth are obtained.

1. Department of Mechanical Engineering, Saga University, 1, Honjo-machi, Saga-shi, Saga 840-8502, Japan 2. Department of Mechanical Engineering, Khulna University of Engineering & Technology, Khulna-9203, Bangladesh 3. School of... more

1. Department of Mechanical Engineering, Saga University, 1, Honjo-machi, Saga-shi, Saga 840-8502, Japan 2. Department of Mechanical Engineering, Khulna University of Engineering & Technology, Khulna-9203, Bangladesh 3. School of Mechanical Engineering, Andong ...

Using Bradshaw's analogy between rotation and stratification, the growth rate of a turbulent wingtip vortex had been analyzed. From Bradshaw's original expression, the effective Richardson number blows up near the region of... more

Using Bradshaw's analogy between rotation and stratification, the growth rate of a turbulent wingtip vortex had been analyzed. From Bradshaw's original expression, the effective Richardson number blows up near the region of maximum azimuthal velocity. According to persistence theory, if the Richardson number is greater than the fourth root of the Reynolds number for a surface stationary with respect to

The lattice Boltzmann method is nowadays a common tool for solving computational fluid dynamics problems. One of the difficulties of this numerical approach is the treatment of the boundaries, because of the lack of physical intuition for... more

The lattice Boltzmann method is nowadays a common tool for solving computational fluid dynamics problems. One of the difficulties of this numerical approach is the treatment of the boundaries, because of the lack of physical intuition for the behavior of the density distribution functions close to the walls. A massive effort has been made by the scientific community to find

The impact and penetration into a moving target is equivalent to the perforation of a stationary target by a "corresponding" yawed projectile. Thus, the semi-empirical model and the numerical simulations that reproduce the experimental... more

The impact and penetration into a moving target is equivalent to the perforation of a stationary target by a "corresponding" yawed
projectile. Thus, the semi-empirical model and the numerical
simulations that reproduce the experimental data for yawed rod
penetration in both normal and oblique impact are also relevant for the
case of moving target perforation. The analytical model is extended
here to assess long rod "erosion" during the perforation of moving
plates. Further numerical simulations were carried out using
AUTODYN 3D-V4. The model and the simulations reproduce many
known characteristics of moving plate perforation. The model predicts
a critical plate velocity above which the rod will not penetrate.

Modern Compressible Flow with historical perspective second edition John D. Anderson, jr.

Los sistemas de alivio de presión son mecanismos diseñados para liberar fluido cuando la presión interna de un recipiente supera un umbral preestablecido. Su misión es evitar fallas estructurales de equipos o tuberías por exceso de... more

Los sistemas de alivio de presión son mecanismos diseñados para liberar fluido cuando la presión interna de un recipiente supera un umbral preestablecido. Su misión es evitar fallas estructurales de equipos o tuberías por exceso de presión, que puedan resultar en una subsecuente explosión, originando importantes pérdidas materiales y humanas.
Debido a múltiples cambios realizados sobre la infraestructura original de la planta compresora C-1, que se encuentra ubicada en la localidad de Temblador, Edo. Monagas, existe incertidumbre sobre si su sistema de alivio seguirá respondiendo eficientemente frente a casos de sobrepresión.
En este trabajo se ha evaluado el efecto que tales cambios han tenido sobre el sistema de alivio de la planta compresora C-1, considerando aquellos escenarios de sobrepresión descritos por la norma API 521 que aplican a las condiciones particulares de esta planta. En los casos en que la respuesta del sistema de alivio ha sido deficiente, se propusieron mejoras.

A nozzle is a relatively simple device that consists of a specifically formed tube that allows hot gases to flow through it. However, the mathematics that describes the nozzle's operation necessitates some thought. Nozzles are available... more

A nozzle is a relatively simple device that consists of a specifically formed tube that allows hot gases to flow through it. However, the mathematics that describes the nozzle's operation necessitates some thought. Nozzles are available in a wide range of forms and sizes. A fixed geometry convergent nozzle is common on simple turbojets and turboprops. A co-annular nozzle is commonly used in turbofan engines. The core flow exits the central nozzle, while the annular nozzle exits the fan flow. The mixing of the two flows increases thrust, and these nozzles are also quieter than convergent nozzles.
A variable geometry convergent-divergent CD nozzle is required for afterburning turbojets and turbofans. The flow in this nozzle first converges down to the smallest area, or throat, before expanding via the divergent segment to the right exit. These nozzles are heavier than fixed geometry nozzles because of the variable geometry, however variable geometry allows more efficient engine running across a larger airflow range than a conventional fixed nozzle. Nozzles are also used in rocket engines to accelerate hot exhaust and generate thrust. A fixed geometry CD nozzle is used in rocket engines, having a significantly greater divergent section than is required for a gas turbine.

In this thesis, several novel numerical methods, including the high-order shock-capturing targeted Essentially Non-oscillatory (TENO) schemes, smoothed-particle hydrodynamics (SPH) based partitioning method and Centroidal Voronoi Particle... more

In this thesis, several novel numerical methods, including the high-order shock-capturing targeted Essentially Non-oscillatory (TENO) schemes, smoothed-particle hydrodynamics (SPH) based partitioning method and Centroidal Voronoi Particle (CVP) domain decomposition method, are proposed and validated. These methods can be used for high-resolution computational fluid simulations and high-performance scientific computing, which are important to study the physics of fluid dynamics.

Summary The edge based Galerkin finite element formulation is used as the basic building block for the construction of multidimensional generalizations, on unstructured grids, of several higher order upwind biased procedures originally... more

Summary The edge based Galerkin finite element formulation is used as the basic building block for the construction of multidimensional generalizations, on unstructured grids, of several higher order upwind biased procedures originally designed for the solution of the 1D compressible Euler system of equations. The use of a central type discretization for the viscous flux terms enables the simulation of multidimensional