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  • 1
    Electronic Resource
    Electronic Resource
    Response of a confined gas to volumetric heating in the absence of gravity. I: Slow transients (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 566-577 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A one-dimensional model for bulk motion induced by a transient volumetric heat source in a confined gas at zero gravity is considered. Rational approximation methods are used to derive a quantitative theory for the gas response to a spatially distributed, time-dependent internal power deposition. The resulting low Mach number compressible flow equations are solved by using perturbation methods. Solutions are given for a conduction-free core and thin conductive boundary layers adjacent to the end walls. It is found that any spatially nonuniform power deposition will cause fluid motion. Net mass transport in the closed container will occur for certain spatially distributed heating. The model mimics the thermal effects of an exothermic gas phase reaction in vapor transport experiments conducted in space. The solutions demonstrate that thermally induced mass transport can be as large as diffusive mass transport in a typical experiment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.858118
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  • 2
    Electronic Resource
    Electronic Resource
    The influence of side wall heat transfer on convection in a confined saturated porous medium (1986)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 29 (1986), S. 349-355 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effect of side wall heat transfer on the stability of natural convection in a vertically oriented finite slab of saturated porous material is considered. All six bounding faces are impermeable. A temperature contrast between the top and bottom horizontal surfaces provides the mechanism for destabilization. The narrow vertical end walls are perfectly insulated. The thermal conditions on the broad vertical side walls range from perfectly insulating to fully conducting as determined by the value of B, the Biot number based on slab height. An asymptotic analysis of the general solution is made in the narrow gap limit ε(very-much-less-than)1, where ε is the cross-slab width-to-height ratio. In this case the relevant heat transfer variable is B¯=εB, the Biot number based on the narrow slab width. In the limit ε → 0 when B¯=O(1), including the case B¯→∞ that corresponds to a linear side wall temperature profile, tall, vertical, three-dimensional, finger-like cells are found at the critical Rayleigh number Rc=π2/ε2. In the limit B¯ → 0 corresponding to perfect insulation, one obtains two-dimensional, O(1) aspect ratio rolls with axes normal to the side walls at the critical value Rc=4π2. These two-dimensional rolls predominate only for B¯=O(ε2), and transition to tall narrow three-dimensional cells occurs when O(ε2)(very-much-less-than) B (very-much-less-than) O(1).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.865718
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  • 3
    Electronic Resource
    Electronic Resource
    Dissociation–recombination relaxation behind a normal shock (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 2777-2785 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Mathematical methods developed originally for thermal explosion theory are used to study the evolution of a dissociation–recombination process occurring in a compressible gas behind a normal shock. The dissociation–recombination reaction, AB+M(large-closed-square)A+B+M, is assumed to have a relatively large dissociation temperature, so that high activation energy perturbation techniques can be used to derive general parameter dependent analytical solutions. Spatial variation of the dependent variables is described in three zones, each of distinct length scale and physical character. Initially, small changes in temperature, concentrations, density, and pressure occur in the relatively high temperature dissociation initiation zone. In the subsequent broader major dissociation region, most of the specie AB is converted to A and B and there are significant variations in all physical variables. In the last and thickest zone, recombination becomes important as the reactive flow evolves to a final equilibrium state. The results provide an analytical counterpart to numerical solutions obtained earlier by Freeman [J. Fluid Mech. 4, 407 (1958)] and Matthews [Phys. Fluids 2, 170 (1959)] for the now classical problem of idealized diatomic gas dissociation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.858166
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  • 4
    Electronic Resource
    Electronic Resource
    Induction zone structure for a high-speed deflagration with variable mole chemistry (1989)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 1 (1989), S. 874-880 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The induction zone characteristics of a planar subsonic high-speed reactive flow downstream of a specific origin are investigated theoretically for the global irreversible reaction F+Ox→νP. The equation of state for the reacting gas mixture is more general than that for a constant molecular weight gas. Perturbation methods based on the limit of high activation energy are used to construct the general parameter-dependent analytical solutions. The dependence of the ignition delay distance on the kinetic, stoichiometric, and flow parameters is discussed in detail. Significantly, it is shown that the reaction with a mole decrement (ν=1) yields the minimum, and a mole increment (ν=3) yields the maximum ignition delay distance when the chemical heat addition and the origin values of parameters are fixed. The physics and length scales found from the perturbation analysis are used as a guide in generating supporting numerical solutions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.857385
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  • 5
    Electronic Resource
    Electronic Resource
    The effect of slab width on the stability of natural convection in confined saturated porous media (1987)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 30 (1987), S. 1941-1947 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Stability boundaries separating different states of bimodal convection in a box of saturated porous material with impermeable bounding faces are determined. Two opposing vertical end walls are always insulated, while the thermal conditions on the other set of opposing vertical side walls range from insulated to perfectly conducting, as measured by the Biot number based on box height. The temperature difference between the hot lower plate and the cooler upper plate provides the mechanism for instability. The eigenvalue problem for the critical Rayleigh number is solved numerically over a range of box sizes and side-wall heat transfer conditions. For small values of the distance H2 between conducting side walls, agreement with previous asymptotic analysis is obtained. New results for boxes with planform dimensions both comparable to the box height show the existence of isolated regions rich in bimodal structure. These islands are separated by broad regions having modal properties identical to those found for conducting side walls in the limit H2→0. The numerical results for O(1) box dimensions continue to exhibit the stabilizing effect of side-wall heat transfer as previously observed for thin slabs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.866208
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  • 6
    Electronic Resource
    Electronic Resource
    Three-dimensional, unsteady, acoustic-shear flow dynamics in a cylinder with sidewall mass addition (1997)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 9 (1997), S. 3753-3763 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Three-dimensional internal flow dynamics are studied in a cylinder with mass injection from the sidewall. A time-dependent, harmonic, non-axisymmetric axial velocity disturbance is imposed on the endwall of the cylinder to create a non-axisymmetric velocity field. An asymptotic analysis is used to reduce the Navier-Stokes equations to more elementary forms in two regions adjacent to the endwall with distinct physical characteristics: an incompressible, inviscid and irrotational core near the endwall, and an incompressible viscous boundary layer containing all three components of vorticity adjacent to the sidewall. Solutions to these equations for disturbance frequencies associated with the lowest order axial acoustic modes show that the non-axisymmetric nature of the flow is confined to the core region adjacent to the endwall with a characteristic axial dimension on the order of the cylinder radius. Within the region, axial, radial, and azimuthal velocities exist. These non-axisymmetric effects decay exponentially fast so that only axisymmetric acoustic modes exist further downstream. These results are valid for driving frequencies below the "cut-off" value that one would find in a duct. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.869513
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  • 7
    Electronic Resource
    Electronic Resource
    Mathematical Modeling for Planar, Steady, Subsonic Combustion Waves (1985)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Fluid Mechanics 17 (1985), S. 267-287 
    Details
    ISSN: 0066-4189
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.fl.17.010185.001411
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  • 8
    Electronic Resource
    Electronic Resource
    The response of a confined gas to a thermal disturbance: rapid boundary heating (1984)
    Springer
    Journal of engineering mathematics 18 (1984), S. 133-156 
    Details
    ISSN: 1573-2703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Technology
    Notes: Summary An inert compressible gas confined between infinite parallel planar walls is subjected to significant heat addition at the boundaries. The wall temperature is increased during an interval which is scaled by the acoustic time of the container, defined as the passage time of an acoustic wave across the slab. On this time scale heat transfer to the gas occurs in thin conductive boundary layers adjacent to the walls. Temperature increases in these layers cause the gas to expand such that a finite velocity exists at the boundary-layer edge. This mechanical effect, which is like a time-varying piston motion, induces a planar linear acoustic field in the basically adiabatic core of the slab. A spatially homogeneous pressure rise and a bulk velocity field evolve in the core as the result of repeated passage of weak compression waves through the gas. Eventually the thickness of the conduction boundary layers is a significant fraction of the slab width. This occurs on the condition time scale of the slab which is typically a factor of 106 larger than the acoustic time. The further evolution of the thermomechanical response of the gas is dominated by a conductive-convective balance throughout the slab. The evolving spatially-dependent temperature distribution is affected by the homogeneous pressure rise (compressive heating) and by the deformation process occurring in the confined gas. Superimposed on this relatively slowly-varying conduction-dominated field is an acoustic field which is the descendent of that generated on the shorter time scale. The short-time-scale acoustic waves are distorted as they propagate through a slowly-varying inhomogeneous gas in a finite space. Solutions are developed in terms of asymptotic expansions valid when the ratio of the acoustic to conduction time scales is small. The results provide an explicit expression for the piston analogy of boundary heat addition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00042732
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  • 9
    Electronic Resource
    Electronic Resource
    An eigenvalue study of a viscous flow separated by mass addition (1974)
    Springer
    Journal of engineering mathematics 8 (1974), S. 229-240 
    Details
    ISSN: 1573-2703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Technology
    Notes: Summary Eigenvalue problem methods, developed for boundary-layer flow are used to consider the spatial stability of the viscous flow past a flat plate which has been separated by mass addition at the surface. A study is made of the rate of approach of a slightly disturbed initial profile to the interaction similarity solution found by Kassoy [1] and Klemp and Acrivos [2]. It is shown that eigenfunctions generated in the separated viscous layer (free shear layer) propagate into the inviscid rotational layer adjacent to the wall. Thus by the inherent interaction process involved, these disturbances affect the external flow as well. The results indicate a relatively slow rate of decay when compared to an attached boundary-layer flow on an impermeable surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02353365
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  • 10
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    Indirect detonation initiation using acoustic timescale thermal power deposition (2013)
    American Institute of Physics
    Details
    Publication Date: 2013-09-01
    Print ISSN: 1070-6631
    Electronic ISSN: 1089-7666
    Topics: Physics
    Published by American Institute of Physics
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