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The behavior of an electrified liquid jet breakup and modes of disintegration were investigated at different flow rates and voltages. The current phenomenology belongs to a new injector introduced recently by Morad et al. (2016). This injector has proven to highly extend the stability and flow rate of electrospray particularly in the Taylor cone-jet mode. The experimental investigation was performed using a high-power light-emitting diode (LED) illumination as the light source. The light source was developed to operate in the pulsing condition when synchronized with a digital camera and was particularly designed to function properly in the presence of high electromagnetic interference (EMI). The details of the light source development were observed through the images captured from the jet breakup at different modes. Finally, the operational map of the new injector was obtained, and the physical mechanisms of different behaviors were examined.

Time delay generates exponential transcendental terms in characteristic equations. Subsequently, the applied methods are narrow to assess the stability map of delayed fractional-order systems with vanishing fractions. In this case, it is convenient to approximate these equations with its integer-order counterparts to design controllers or investigate features of the systems. However, delay can cause enormous differences between characteristic of these two equations. This study offers a method to survey analytically the stability of fractional-order time delayed linear time invariant systems with infinitesimal fractions. In this method, equations are transferred to an explicit expression which enables one to analyse stability of retarded, neutral and even integer-order systems simultaneously.

In the present work, design procedure and computer simulation of an AUV are documented briefly. The design procedure containing the design of propulsion system and CFD simulation of hydrodynamics behavior of the hull leads to achieve an optimum mechanical performance of AUV system. After designing, a comprehensive one dimensional model including motor, propeller, and AUV hull behavior simulates the whole dynamics of AUV system. In this design, to select the optimum AUV hull, several noses and tails are examined by CFD tools and the brushless motor is selected based on the first order model of DC electrical motor. By calculating thrust and velocity in functional point, OpenProp as a tool to select the optimum propeller is applied and the characteristics of appropriate propeller are determined. Finally, a computer program is developed to simulate the interaction between different components of AUV. The simulation leads to determine the initial acceleration, final velocity, and angular velocity of electrical motor and propeller. Results show the final AUV performance point is in the maximum efficiency regions of DC electrical motor and propeller.

An extended Taylor cone-jet mode is experimentally characterized using a recently introduced hemispherical nozzle. Ethanol is used as the working fluid, and the nozzle produces a much broader range of flow rate and stability of the cone-jet mode. High-resolution images are captured using a high-power light-emitting diode in precise lighting operations to characterize the liquid behavior. Various regimes in the extended cone-jet mode are recognized and mapped in a plane of electro-Weber and Bond numbers. The cone profiles are quantified regarding dimensionless groups, and a related self-similarity is introduced. The cone elongates with the electro-Weber number but retracts as the Bond number increases. The cone and jet diameters are also quantified from the nozzle exit to where the jet begins a transition to instability. It is shown that jet diameter increases with the electro-Weber number powered by 0.75, but it is independent of the Bond number. The meniscus lengths are reported at different electro-Weber and Bond numbers too, and the corresponding correlations are obtained. Finally, jet whipping and spray envelopes are illustrated at various dimensionless numbers, while a wider spray envelope and a dual distribution are recognized at higher electro-Weber numbers.