Jets, ie collimated streams of matter, occur from the microscale up to the large-scale structure of the universe Our focus will be mostly on surface tension effects, which result from the cohesive properties of liquids Paradoxically, cohesive forces promote the breakup of jets, widely encountered in nature, technology and basic science, for example in nuclear fission, DNA sampling, medical diagnostics, sprays, agricultural irrigation and jet engine technology Liquid jets thus serve as a paradigm for free-surface motion, hydrodynamic instability and singularity formation leading to drop breakup In addition to their practical usefulness, jets are an ideal probe for liquid properties, such as surface tension, viscosity or non-Newtonian rheology They also arise from the last but one topology change of liquid masses bursting into sprays Jet dynamics are sensitive to the turbulent or thermal excitation of the fluid, as well as to the surrounding gas or fluid medium The aim of this review is to provide a unified description of the fundamental and the technological aspects of these subjects

Physics of liquid jets

Chemical kinetic modeling of hydrocarbon combustion

We present a new numerical code, PLUTO, for the solution of hypersonic flows in 1, 2, and 3 spatial dimensions and different systems of coordinates. The code provides a multiphysics, multialgorithm modular environment particularly oriented toward the treatment of astrophysical flows in presence of discontinuities. Different hydrodynamic modules and algorithms may be independently selected to properly describe Newtonian, relativistic, MHD, or relativistic MHD fluids. The modular structure exploits a general framework for integrating a system of conservation laws, built on modern Godunov-type shock-capturing schemes. Although a plethora of numerical methods has been successfully developed over the past two decades, the vast majority shares a common discretization recipe, involving three general steps: a piecewise polynomial reconstruction followed by the solution of Riemann problems at zone interfaces and a final evolution stage. We have checked and validated the code against several benchmarks available in literature. Test problems in 1, 2, and 3 dimensions are discussed.

https://iopscience.iop.org/article/10.1086/513316/pdf

PLUTO: A Numerical Code for Computational Astrophysics

Use of breakup time data and velocity history data to predict the maximum size of stable fragments for acceleration-induced breakup of a liquid drop

Pulse detonation propulsion : challenges, current status, and future perspective

High velocity gas stream induced shattering of liquid drops, disintegration rate and breakup time

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Aerodynamic shattering of liquid drops.

A method for calculating the position of the first normal shock, or Mach disc, in the jet behind a highly underexpanded nozzle is presented. In the calculation for a sonic orifice, the axial pressure distribution on the centerline of the flow behind the orifice, calculated by the method of characteristics, is used to define a fictitious nozzle extension, and the shock is then assumed to exist at that point where atmospheric pressure would be attained behind the shock—i.e., the shock is assumed to exist at the end of the fictitious nozzle extension. Physical arguments are then employed to extend this calculation to nozzles with supersonic exit Mach Numbers. The results compare favorably with experimental data. An approximate method for computing the jet boundary up to the point of maximum jet area is given, and the results are compared both with photographs of actual jets and with jet boundaries calculated by the method of characteristics. Favorable agreement exists at relatively low nozzle pressure ratios.

On the structure of jets from highly underexpanded nozzles into still air : final report

The feasibility of a reaction device operating on intermittent gaseous detonation waves is considered. The results of a simplified theoretical analysis are presented and discussed. Preliminary experiments were conducted to determine the impulse derived from a single detonation wave and to investigate some of the more influential parameters: These tests were effected by suspending the detonation tube as a pendulum. A cyclic detonation tube was designed and operated utilizing hydrogen-air mixtures. Measurements of thrust, fuel flow, air flow, and temperatures were obtained over a range of operating conditions. Specific impulses of over 2100 sec were realized, which was in good agreement with the predicted performance.

Intermittent Detonation as a Thrust-Producing Mechanism

and Propulsion Colloquium, NATO-AGARD, Palermo, Sicily, March 17-21, 1958. 28 Lees, L., ' 'Laminar Heat Transfer Over Blunt-Nosed Bodies at Hypersonic Flight Speeds,\" J E T PROPULSION, vol. 26, no. 4, 1956, pp. 259-269. 29 Liepmann, H. W., and Bleviss, Z. O., \"The Effects of Dissociation and Ionization on Compressible Couette Flow,\" Douglas Aircraft Co., Report SM-19831, 1956. 30 Lighthill, M. J., \"Dynamics of a Dissociating Gas, I-Equilibrium Flow,\" Journal of Fluid Mechanics, vol. 2, part 1, 1957, pp. 1-32. 31 Linnett, J. W., and Marsden, D. G. H., \"The Kinetics of the Recombination of Oxygen Atoms at a Glass Surface,\" and \"The Recombination of Oxygen Atoms on Salt and Oxide Surfaces,\" Proceedings of the Royal Aeronautical Society, Series A, no. 1199, vol. 234, March 1956, pp. 489-515. 32 Logan, J. G., Jr., \"Relaxation Phenomena in Hypersonic Aerodynamics,\" Paper presented at IAS 25th Annual Meeting, Jan. 28-31, 1957 (IAS Preprint 728). 33 Meixner, J., \"Zur Theorie der Warmeleitfahigkeit Reagierender Fluider Mischungen,\" Z. Naturforsch, vol. 7a, 1952, pp. 553-557. 34 Metzdorf, H. J., \"Flows in Partly Dissociated Gases,\" Journal of The Aeronautical Sciences, vol. 25, no. 3, 1958, p. 200. 35 Moore, L. L., \"A Solution of the Laminar Boundary Layer Equations for a Compressible Fluid with Variable Properties, Including Dissociation,\" Journal of the Aeronautical Sciences, vol. no. 8, 1952, pp. 505-518. 36 Nernst, W., \"Chemisches Gleichgewicht und Temperaturgefallen,\" Festschrift Ludwig Boltzmann Gewidmet, 1904, pp. 904-915. 37 Penner, S. S., \"Chemical Reactions in Flow Systems,\" NATO-AGARD, Butterworths, London, 1955. 38 Penner, S. S., Harshbarger, F., and Vali, V., \"An Introduction to the Use of the Shock Tube for the Determination of Physico-Chemical Parameters,\" Combustion Researches and Reviews, NATO-AGARD, Butterworths, London, 1957, pp. 134-172. 39 Prigogine, I., and Buess, R., Acad. Roy ale de Belgique, vol. 38, series 5, 1952, pp. 711-851.

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A Preliminary Study of the Application of Steady-State Detonative Combustion to a Reaction Engine

The velocity decrement of a gaseous detonation propagating through a channel with a compressible, nonreacting boundary is investigated experimentally and theoretically. The decrement depends on the width of the channel, the reaction length of the gaseous explosive, and the ratio of the explosive to inert-gas densities. In the experiments, the gaseous explosive was separated from the boundary gas by a very thin film (≈250) to eliminate any diffusion effect. Extensive experimental results for H2−O2 mixtures bounded by nitrogen, and some results on stoichiometric CH4−O2, show a general agreement with theory. In the case of H2−O2 mixtures, minimum channel width at which the wave continues to propagate is determined. It is found that a velocity decrement beyond 8%–10% leads to quenching, which appears to be best predicted by Belles' explosion-limit criterion. Using velocity decrement data, the reaction lengths of the stoichiometric mixtures of H2−O2 and CH4−O2 are found to be 0.11 in. and 0.26 in., respectively. Experimental results on the deflection angle of the interface and the shock induced by the detonation wave into the inert gas, are also presented. They show good agreement with a theory based on a shock-tube analogy.

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James Arthur Nicholls

Papers

Aerodynamic shattering of liquid drops.

On the structure of jets from highly underexpanded nozzles into still air : final report

Intermittent Detonation as a Thrust-Producing Mechanism

A Preliminary Study of the Application of Steady-State Detonative Combustion to a Reaction Engine

The influence of a compressible boundary on the propagation of gaseous detonations