Instability of a liquid jet subject to disturbances composed of two wavenumbers

Huynh, Huy H.; Mashayek, Farzad

doi:10.1017/s0022112096007501

Cited by 13 publications

(3 citation statements)

References 15 publications

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“…The relative size of the satellite droplets increases when the perturbation wavelength increases (Rutland & Jameson 1970); experiments show that below a dimensionless wavenumber kR 0 ≈ 0.2, where k is the wavenumber of the perturbation and R 0 is the radius of the unperturbed jet, the volume contained in the satellite droplet is Control of jet breakup by using two Rayleigh-Plateau-unstable modes 277 even larger than the main droplet. By adding higher harmonics to the actuation signal, the size and speed of the satellite droplet can be influenced (Chaudhary & Maxworthy 1980;Huynh, Ashgriz & Mashayek 1996). Another way to reduce or eliminate the satellite droplets is to induce coalescence between multiple main droplets.…”

Section: Introductionmentioning

confidence: 99%

Control of jet breakup by a superposition of two Rayleigh–Plateau-unstable modes

et al. 2014

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We experimentally, numerically and theoretically demonstrate a novel method of producing a stream of widely spaced high-velocity droplets by imposing a superposition of two Rayleigh-Plateau-unstable modes on a liquid jet. The wavelengths of the two modes are chosen close to the wavelength of the most unstable mode. The interference pattern of the two superimposed modes causes local asymmetries in the capillary tension. The velocity of the initial droplets depends on these local asymmetries. Due to their different velocities, the droplets coalesce to produce a stream of larger droplets spaced at a much larger distance than the initial droplets. We analytically derive the perturbations that robustly induce this process and investigate the influence of the nonlinear interactions of the two Rayleigh-Plateau-unstable modes on the coalescence process. Experiments and numerical simulations demonstrate that the jet breakup and the subsequent droplet merging are fully governed by the selected modes.

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Section: Introductionmentioning

confidence: 99%

Control of jet breakup by a superposition of two Rayleigh–Plateau-unstable modes

et al. 2014

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“…Also, as Laryea and No indicate, controlling atomization can be used in reducing the amount of pesticides in agricultural sprays as well as in increasing the deposition. The presence of extra disturbances at other frequencies was demonstrated while measuring the actual motion of the vibrating element by Rohani et al 16 Huynh et al 17 study the effects of composite disturbances on breakup and describe the nonlinear interaction between the components of a disturbance composed of second and third harmonics and their effects on breakup. However, rectilinear streams provide an opportunity for fine control of droplet properties and trajectories.…”

Section: Introductionmentioning

confidence: 99%

Breakup control of a liquid jet by disturbance manipulation

Rohani¹,

Jabbari²,

Dunn‐Rankin³

2010

Physics of Fluids

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Computation of effective free surfaces in two phase flows Phys. Fluids 24, 087101 (2012) Stability analysis and control of the flow in a symmetric channel with a sudden expansion Phys. Fluids 24, 084102 (2012) The dynamics of liquid drops and their interaction with solids of varying wettabilities Phys. Fluids 24, 082001 (2012) Note: Pneumatically modulated liquid delivery with feedback control Rev. Sci. Instrum. 83, 076102 (2012) Additional information on Phys. FluidsIn this paper, we study the breakup of a circular jet subject to a manipulated disturbance applied by an actuator ͑here a piezoelectric͒ in order to control droplets sizes and patterns over a wide range. According to previous studies, breakup of a jet is strongly affected by the characteristics of the disturbance. When the breakup is not periodic and repeatable, it is described as an irregular or random breakup. On the other hand, over a frequency range for the disturbance, the breakup can be made repeatable, though not necessarily uniform, in which the droplets pinch off the stream at a constant rate. In this case, the breakup is called regular, although satellites or secondary droplets might form among the main droplets. In most applications, a very narrow frequency range ͑much narrower than the regular breakup frequency range͒ is used for operation, since it is the only range where uniform droplets form. This work demonstrates that by eliminating secondary droplets or satellites, the entire regular breakup regime becomes available for desirable operation, i.e., uniform droplet generation. The regular breakup regime is specified experimentally and an additional disturbance is added to the driving disturbance in order to eliminate the nonuniform droplets. This method provides us with droplets of the desired size when they cannot be produced with a single frequency disturbance alone. The results also demonstrate that different frequencies for the additional disturbance produce different patterns for the droplets sizes.

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“…Satellite drop formation subjected to a monochromatic perturbation instability was investigated by Ashgriz and Mashayek (1995). Huynh et al (1996) considered the case of viscous capillary jets subject to disturbances consisting of two superposed wave numbers.…”

Section: Introductionmentioning

confidence: 99%

The study of the behaviour of a disturbed semi-infinite liquid jet using a spatial instability method

Basu

2001

Fluid Dyn. Res.

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A study has been made of the behaviour of a disturbed semi-inÿnite liquid jet using a spatial instability method. A sinusoidal disturbance in the axial component of jet velocity at the nozzle is considered which resulted in an elliptic free surface boundary value problem with two non-linear boundary conditions. The system is linearised using perturbation techniques and the ÿrst order solution resulted in the dispersion relation. The jet stability is found to depend explicitly on the frequency of the disturbance and the Weber number. The second and third order solutions have been derived analytically which are used to predict on jet break-up and satellite formation.

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Instability of a liquid jet subject to disturbances composed of two wavenumbers

Cited by 13 publications

References 15 publications

Control of jet breakup by a superposition of two Rayleigh–Plateau-unstable modes

Control of jet breakup by a superposition of two Rayleigh–Plateau-unstable modes

Breakup control of a liquid jet by disturbance manipulation

The study of the behaviour of a disturbed semi-infinite liquid jet using a spatial instability method

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