Experiments on Water Drop Breakup Behind Mach 3 to 12 Shocks.

Reinecke, W. G.; Mckay, W. L.

doi:10.2172/4160011

Cited by 29 publications

(13 citation statements)

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“…We note that it has some similarities with the 'bag and stamen' breakup mechanism observed at much lower Weber numbers. An important consequence is that such a filament, if real, could not have been resolved with the X-ray diagnostics used by Reinecke to see 'through' the mist, and which led him to diminish his total breakup time estimate [15,19]. However, the mass contained in this filament is far from negligible, as will be discussed in Sect.…”

Section: Droplet Deformationmentioning

confidence: 99%

“…If we focus on experimental data with water droplets, several studies can be found for W e between 10 3 and 10 4 [12,16,17]. However, only a few concern W e between 10 4 and 10 5 [15,[17][18][19], and even fewer concern W e greater than 10 5 [15,19]. Thus, it appears that there is a need for new experimental data to investigate the breakup mechanisms in this regime.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of mechanisms leading to water drop breakup at Mach 4.4 and Weber numbers above 105

et al. 2019

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The paper presents an investigation on water drop breakup in the 'catastrophic' mode at Weber numbers above 10 5. Experimental data have been obtained on a detonation shock tube operated at a Mach number between 4.2 and 4.6. Displacement and deformation of the mist cloud generated around the droplet were observed with a shadowgraph system, and Schlieren imagery was used to visualise the bow and wake shocks around the droplet. We observe that all measured quantities scale with the initial drop diameter. In order to analyse the experimental results and relate these observables to the breakup process, numerical hydrodynamic simulations have been performed. Once validated by direct comparison with our experimental observations, the simulation results are used to see "through" the mist and infer the droplet evolution with dimensionless time T. According to our results, the breakup mechanism can be divided into 3 steps. First (T < 1), most of the liquid mass remains in one main drop, whose shape flattens due to the hydrodynamic forces; then (1 < T < 2) fragmentation begins along the outer rim of the liquid drop and splits the corresponding mass into two parts; the first spreads out radially in small fragments while the remains finally (2 < T < 3.5) take the shape of a filament aligned with the flow. Our results are consistent with a complete breakup time T b = 5.5.

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Section: Droplet Deformationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigation of mechanisms leading to water drop breakup at Mach 4.4 and Weber numbers above 105

et al. 2019

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“…In shock-tube coordinates, the distance between the shock wave and the drop is given by s = u s t -x (7) Since P2 = Poo/£> "2 = (1 -e)i* s (8) Equations (1) and (7) In relating this equation to the case of flight through the atmosphere, we interpret u s as the flow velocity component normal to the shock wave: in the stagnation region, the freestream velocity V^ ; in the conical-flow region, the velocity component V^ sin 0 S , where 9 S is the inclination of the shock wave. In what follows, we shall be concerned only with conditions at impact on the vehicle surface.…”

Section: Drop Breakup Calculations Under Flight Conditionsmentioning

confidence: 99%

Raindrop Breakup in the Shock Layer of a High-speed Vehicle

1972

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The problem of predicting raindrop breakup effects in the shock layer of a high-speed vehicle is discussed. Relevant experimental data, obtained in a shock tube with shadowgraph and x-ray photography, are presented in the form of correlations of the nondimensional time to breakup with the Weber number, together with the drop mass variation and trajectory as a function of nondimensional time. The relationship between the experimental situation and the flight case is delineated for the stagnation and downstream conical-flow regions of a high-speed shock layer. Based on the experimental correlations, calculations are made of the impacting drop mass fractions, velocities, and impact angles for a vehicle traversing a rainstorm.

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“…The following discussion of past research on secondary breakup is brief, see Hsiang & Faeth (1992), Wierzba & Takayama (1987), Giffen & Muraszew (1953), Hinze (1955), Krzeczkowski (1980), and references cited therein, for more complete reviews. High-speed photography has been used to identify secondary breakup regimes for shock-wave disturbances (Hinze 1955;Hanson et al 1963;Reinecke & McKay 1969;Reinecke & Waldman 1970;Ranger & Nicholls 1969;Gel'fand et al 1974;Krzeczkowski 1980;Wierzba & Takayama 1988). Bag breakup is observed at the onset of secondary breakup.…”

Section: Introductionmentioning

confidence: 99%

Drop properties after secondary breakup

Hsiang

Faeth

1993

International Journal of Multiphase Flow

168

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Drop properties during and after secondary breakup in the bag, multimode and shear breakup regimes were observed for shock-wave-initiated disturbances in air at normal temperature and pressure. Test liquids included water, n-heptane, ethyl alcohol and glycerol mixtures to yield Weber numbers of 15-600, Ohnesorge numbers of 0.0025-0.039, liquid/gas density ratios of 579-985 and Reynolds numbers of 1060-15080. Measurements included pulsed shadowgraphy and double-pulsed holography to find drop sizes and velocities after breakup. Drop size distributions after breakup satisfied Simmons' universal root normal distribution in all three breakup regimes, after removing the core (or drop-forming) drop from the drop population for shear breakup. The size and velocity of the core drop after shear breakup was correlated separately based on the observation that the end of drop stripping corresponded to a constant Ertvrs number. The relative velocities of the drop liquid were significantly reduced during secondary breakup, due both to the large drag coet~cients caused by drop deformation and the reduced relaxation times of smaller drops. These effects were correlated successfully based on a simplified phenomenological theory.

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Experiments on Water Drop Breakup Behind Mach 3 to 12 Shocks.

Cited by 29 publications

References 0 publications

Investigation of mechanisms leading to water drop breakup at Mach 4.4 and Weber numbers above 105

Investigation of mechanisms leading to water drop breakup at Mach 4.4 and Weber numbers above 105

Raindrop Breakup in the Shock Layer of a High-speed Vehicle

Drop properties after secondary breakup

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