A transient analysis to quantify droplet deformation under DC electric fields is presented. The full Taylor-Melcher leaky dielectric model is employed where the charge relaxation time is considered to be finite. The droplet is assumed to be spheroidal in shape for all times. The main result is an ODE governing the evolution of the droplet aspect ratio. The model is validated by extensively comparing predicted deformation with both previous theoretical and numerical studies, and with experimental data. Furthermore, the effects of parameters and stresses on deformation characteristics are systematically analyzed taking advantage of the explicit formulas on their contributions. The theoretical framework can be extended to study similar problems, e.g., vesicle electrodeformation and relaxation.

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This paper explains the physical behavior of the electron density of high-power and large-volume plasma wind tunnel using a single channel hydrogen cyanide (HCN) laser interferometer. Based on the characteristics of inductively coupled plasma (ICP)-heated wind tunnel, the temperature and pressure distribution of the ICP-heated wind tunnel are obtained from numerical simulations, during which the influence of neutral particles is considered to calculate the accurate electron density. The typical electron density order of ICP-heated wind tunnel is [Formula: see text]. We discovered that there is a positive correlation between the electron density of argon plasma jet and mass flow rate, while that of air plasma jet decreases slightly. We also found that the peak of electron density appears when the argon is switched to air. Within the voltage range of 6–10 kV, the electron density of argon and air plasma increases slowly. However, when the voltage increases from 10 to 12 kV, the electron density of air plasma increases sharply with the mass flow rate of 15 g/s. Finally, the electron density of argon plasma is much higher than that of air plasma at the same mass flow rate and voltage.

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In the development of bottom water sandstone reservoir, the utilization of horizontal wells is economical and reliable but also can delay the bottom water coning and it has the advantages over the conventional vertical wells .The methods adopted in the past have methodological errors. This paper regards the reservoir flow and wellbore flow of horizontal well as a interactional system which considers the fluid friction, momentum change, the mixed interference of wellbore wall inflows and other complex factors and obtains Laplace space solution by using the Laplace transform to establish the coupled model of wellbore pressure drop calculation. It can provide more advanced means for reservoir engineering studies, well completion and production engineering design of horizontal wells on the conditions of bottom water reservoir.

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A plasma sheath will be generated around the hypersonic vehicle during reentry, and a large number of electrons in the plasma sheath will seriously affect the communication between the vehicle and the ground station. In order to reduce the electron number density of the hypersonic vehicle plasma sheath, a method of using pulsed discharge active actuation to regulate the plasma sheath is proposed. Based on the air dissociation and ionization model including 11 components and 32 chemical reactions, the reduction effect of pulsed discharge actuation on the electron density of plasma sheath is studied by numerical simulation. A first test is performed in which the pulsed discharge is compared with the plasma jets' experimental data. Then, a second test compared the plasma flow field around the RAMC-II vehicle with the flight test and NASA data. In these two tests, the simulation results are basically consistent with the experimental results. Finally, the effect of pulsed discharge with different energy density on the plasma sheath electron density is studied. The numerical results show that the interaction between the high-pressure aerodynamic actuation generated by the actuator and the plasma sheath produces an obvious shock wave, which blocks electrons from flowing downstream, reduces the velocity and pressure of the flow field behind the shock wave, and, finally, makes the electron density downstream of the actuator attenuate significantly, with the maximum attenuation amplitude of about 35%. Compared with the traditional method, the method proposed in this paper requires less space, load, and source power and has certain engineering feasibility.

In the diagnosis of plasma microwave transmission, when the plasma size is large and the electron density is high, the microwave will cause a phase period ambiguity problem. In order to solve the phase ambiguity, a novel method of using the phase shift group delay (PSGD) to recover the true phase shift is proposed. The PSGD method is used to recover the simulated phase shift and diagnose the plasma. The diagnostic accuracy is all greater than 91%, which verifies the method. And the new method is used to diagnose the real inductively coupled plasma with high precision. Through analysis, the method of group delay recover phase shift is more suitable for stable plasma or slow-varying plasma.