This work considers the compressible flow field established in a rectangular porous channel. Our treatment is based on Rayleigh–Janzen perturbation applied to inviscid steady two-dimensional isentropic equations. Closed-form expressions are then derived for main properties of interest. analytical results verified via numerical simulation, with laminar and turbulent models, available experimental data. They also compared existing one-dimensional theory previous pseudo-one-dimensional...

In this paper, we discuss the merits of two models for swirl velocity in core a confined bidirectional vortex. The first is piecewise, Rankine-like, based on combined-vortex representation. It stems from notion that uniform shear stress distribution may be assumed inner vortex region cyclone, especially at high Reynolds numbers. Thereafter, direct integration enables us to retrieve an expression overcomes inviscid singularity centreline. second model consists modified asymptotic solution...

The object of this study is to canvas the literature for purpose identifying and compiling a list Gaps, Obstacles, Technological Challenges in Hypersonic Applications (GOTCHA). significance GOTCHA related deficiencies discussed along with potential solutions, promising approaches, feasible remedies that may be considered by engineers pursuit next generation hypersonic vehicle designs optimizations. Based on synthesis several modern surveys public reports, cohesive formed consisting widely...

In this study, the Bragg–Hawthorne equation (BHE) is extended in context of a steady, inviscid and compressible fluid, thus leading to an assortment partial differential equations that must be solved simultaneously. A solution pursued by implementing Rayleigh–Janzen expansion square reference Mach number. The corresponding formulation subsequently used derive approximation for Trkalian model bidirectional vortex. approximate compared representative computational fluid dynamics simulation...

Stodola’s area-Mach number relation is one of the most widely used expressions in compressible flow analysis. From academe to aeropropulsion, it has found utility design and performance characterization numerous propulsion systems; these include rockets, gas turbines, microcombustors, microthrusters. In this study, we derive a closed-form approximation for inverted more commonly solution relating directly nozzle area ratio. The expression provides computationally efficient alternative...

The intent of this study is to evaluate existing gaps in computational fluid dynamics (CFD) technology with an emphasis on hypersonic flow modeling. importance validation highlighted, especially respect the dearth available data. Modeling challenges relevant air-breathing propulsion, such as multi-phase and turbulent mixing, are discussed areas for continued research identified. Two specialized codes (DPLR VULCAN) two general purpose solvers (CFD++ FLUENT) also reviewed use applications.

The Bragg-Hawthorne equation, also named Squire-Long, takes advantage of a requirement that the stagnation pressure head, H, and angular momentum, B, may be generally related to stream function, . This reduces Navier-Stokes equations single function representation, wherein H B specified based on application interest. In this paper, equation (BHE) is extended in context steady, inviscid, compressible fluid. Then given an assortment suitable assumptions, our approach leads pair partial di...

A combination of microwave heating and radiometry provides a promising means the noninvasive measurement blood perfusion. In this paper, system, along with perfusion mimicking setup, for perfusion/flow is described. This paper also presents first time i) considerations achieving high sensitivity temperature response versus flow, ii) radiometric decay at presence iii) proper choice phantom to mimic tissue permittivity, iv) insights on frequencies from near-field antenna beam bioheat transfer...

We consider the compressible flow analogue of solution known colloquially as Hart-McClure profile. This potential motion is used to describe mean in original energy-based combustion instability framework. In this study, we employ axisymmetric form equation for steady, inviscid, irrotational assuming uniform injection a calorically perfect gas porous, right-cylindrical chamber. expanded order ${\bf M}_{\rm w}^4 $Mw4 using Rayleigh-Janzen sequence powers w}^{\rm 2} $Mw2, where Mw wall Mach...

The purpose of this paper is to develop a theoretical solution that describes the compressible bidirectional vortex. Similar studies by authors have extended Taylor and Culick profiles incorporate effects compressibility in porous channels tubes. Our study prompted need better understand flow behavior at high speed swirl-driven thrust chambers which reversing cyclonic motion established. Such advantage promoting mixing, efficiency, internal wall cooling. This accomplished confining...

The primary goal of this work is to assess the sensitivity bidirectional vortex changes in injection conditions. To achieve goal, a parametric model developed capture effect variations injector quantity, size, velocity, and location. resulting cold-flow simulated using OpenFOAM, an open-source platform for solution fluid dynamics problems. accuracy solver validated through comparisons existing analytical models. After validation, velocity pressure profiles are examined response structure...

In this article, we review several inviscid, helical solutions that are developed in the context of cyclonic, swirl-driven combustors. Specifically, survey focuses on three solutions: an exact inviscid solution, a heuristic model for swirl velocities, and compressible vortex derived from modified form Bragg-Hawthorne equation. As part endeavor, overview derivations assumptions is provided. The structures resulting then contrasted by comparing their velocity fields. all cases outer region...

The isentropic flow equations relating the thermodynamic pressures, temperatures, and densities to their stagnation properties are solved in terms of area expansion specific heat ratios. These fundamental thermofluid relations inverted asymptotically presented arbitrary order. Both subsonic supersonic branches possible solutions systematically identified exacted. Furthermore, for each branch solutions, two types recursive approximations provided: a property-specific formulation more general,...

The focus of this paper is the numerical prediction flow trajectories for particles that may be entrained in a bidirectional vortex, swirling has reversing axial character. internal flowfield we consider germane to both cylindrical cyclone separators and swirl-dominated thrust chambers make use favorable mixing centrifugal properties vortex. To end, Lagrangian tracking scheme employed determine motion inert are subject Stokes Faxen drag addition other ancillary contributions due virtual...

The focus of this paper is the theoretical prediction trajectories solid particles leaving surface a propellant grain in cylindrically-shaped rocket motor (SRM). Lagrangian particle trajectory modeled while taking into account contributions due to drag, virtual mass, Saffman lift, gravity, and buoyancy forces Stokes flow regime. For conditions associated with simulated SRM, it determined that two dominant affecting are drag gravitational forces. Thus using oneway coupling paradigm, effects...

, a closed-form representation of the compressible correction. In view favorable convergence properties Rayleigh- Janzen expansion, resulting approximation can be relied upon from headwall down to sonic point and slightly beyond in long porous tube or nozzleless chamber. Based on simple expressions that prescribe this motion, principal flow attributes are quantified parametrically compared existing incompressible one-dimensional theories. effort, local Mach number pressure calculated shown...