I. A. Moralev

Experimental study of electrical discharges in gas flows under external magnetic field

The results of experimental investigation of the evolution, dynamics, and electrical characteristics of discharges in gas medium, gas flow, and gas counter flows in an external magnetic field for a large range of parameters are presented. The description of mechanisms of spiral discharge evolution, movement of discharge attachment point to the external electrode, rotation of the discharge channel, and secondary breakdown are presented.

Structure of RF capacitive discharge in swirl airflow at atmospheric pressure

Conditions for the onset of transitions between corona and pinch types of one-electrode radiofrequency capacitive discharges in swirl airflow at atmospheric pressure have been analyzed. It is established that the transitions observed at various values of the gas flow rate and swirl parameter are related primarily to the gasdynamic structure of airflow. Calculated data obtained in the framework of a proposed theoretical model are qualitatively consistent with the available experimental data.

Aerodynamic quality management for the NACA 23012 airfoil model using the surface high-frequency discharge

The effect of the surface capacity HF discharge on airfoil flow-around has been studied in the situation when the oncoming flow velocity is 20 m/s and the Reynolds numbers are Re = 105. The power delivered to discharge was modulated with a frequency of 3 × 102–2 × 104 Hz, which corresponds to a Strouhal number of St = 1.2–80, and the average electric power (Wav) was 50–400 W. It has been indicated that the aerodynamic drag decreased and the lift increased at stall and post-stall angles of attack when the HF dielectric barrier discharge was turned on. A nonstationary stochastic change in the Cx and Cy aerodynamic characteristics was observed at a stall angle in the St = 4–10 range of Strouhal numbers when the power was insufficient (Wav ≈ 100 W).

Effect of dielectric barrier discharge on wing-tip vortex formation

The formation of vortex trace behind a finite-span model airfoil has been studied by the method of stereoscopic particle image velocimetry. It is established that a dielectric barrier discharge initiated at the airfoil tip surface influences the wing-tip vortex formation.

The evolution of instabilities in gas microjets under acoustic action

The results of an experimental investigation of the effect of external acoustic perturbations on the stability of millimeter- and submillimeter-scale gas jets flowing out into the atmosphere are presented. Data on flow visualization by the shadow method and the instantaneous velocity fields of the flow by the PIV method are obtained. The sound effect in the jet is shown to lead to the asymmetric mode of instability. The growth of this mode downstream leads to flow bifurcation. Frequency characteristics of the effect for jets of different geometries and jets of different gases are compared.

Edge effects in flow around a plasma actuator

We have studied the structure of flow formed in the boundary layer at the lateral edge of the discharge zone of a dielectric barrier discharge plasma actuator. It is established that a region with nonzero component of tangential velocity exists near the plasma layer boundary. At some distance downstream of the actuator, a concentrated vortex is formed with the axis aligned with the flow direction. In the presence of two closely spaced boundaries of the plasma region, a pair of counter-rotating vortices is formed. Separate microdischarges in the plasma layer also appear to be a source of similar longitudinal vortices with smaller amplitude.

Streamlining of a cylinder with an electric arc rotating in a magnetic field

Streamlining of a circular cylinder with a localized heat source modeling an MHD actuator in which the plasma arc channel moves along the cylinder surface under the action of the Lorentz force in a radial magnetic field is studied experimentally and simulated numerically. It is shown that the presence of a moving heat release region leads to a break in the symmetry in cylinder streamlining by the external flow and the appearance of a nonzero lift force and circulation.

Features of the transverse discharge glow depending on the gas flow rate in a vortex chamber

Experimentally observed features in the formation of glowing zones in gas discharge at various mass flow rates are qualitatively explained based on the numerical simulation of a turbulent swirling flow with a local source of heat release.

Air flow control around a cylindrical model induced by a rotating electric arc discharge in an external magnetic field. Part II

The structure and dynamics of a near-wall gas flow produced by a rotating electric arc discharge in an external magnetic field around a cylindrical model without an incoming flow has been investigated. The electric arc on the model has been produced by a combined electric discharge (low-current rf discharge + high-current pulse-periodic discharge). Permanent magnets with induction B ≈ 0.1 T have been placed inside the cylindrical models. Ring electrodes are arranged on the surface of the model. The structure and dynamics of the near-wall gas flow around the cylindrical model have been investigated using high-speed photography, as well as the shadowgraph and particle image velocimetry (PIV) methods.

Experimental Study of the Development of a Helium Jet during Acoustic Action

A helium jet subjected to acoustic action is experimentally studied by the particle image velocimetry method. The mechanisms of flow stability loss are discussed. An asymmetric instability mode is shown to develop in the jet subjected to the action of sound, which leads to jet division. Jet vibrations are found to be accompanied by a secondary instability, which manifests itself in the formation of vortices inside the jet.