Yury Selyutskiy

Methods of qualitative analysis in the problem of rigid body motion in medium

The present paper describes the application of methods of qualitative analysis in the classical problem of rigid body motion in medium. Three particular problems are used as examples: bolides flight, galloping of aeroelastic constructions, and behavior of horizontal axis wind turbine. It is shown that this approach reveals the general properties of the behavior of objects studied, such as impossibility of translational deceleration of bolides and the presence of hysteretic phenomena in the operation of wind turbines.

Wind Turbine Based on Antiparallel Link Mechanism

A new type of wind turbine is proposed. A blade is attached to a connected rod of an antiparallel link mechanism. The blade interacts with air flow. A rotor of an electrical generator is fixed on an axis of a crank. The mathematical model of electro-mechanical system is constructed. The interaction between blade and flow is described using quasi-static approach. A working regime of the turbine corresponds to an attracting periodic trajectory of the dynamic system. Sufficient conditions of existence of such periodic trajectories are obtained by the Poincare-Pontryagin asymptotic method. Bifurcation diagrams are constructed. A prototype is tested in a wind tunnel.

On oscillations of a plate near the “across-the-flow” equilibrium

An elastically mounted plate is considered that is placed in in flow and can rotate about the axis passing through its center and parallel to the longer side of the plate. In the equilibrium, the plate is perpendicular to the flow. In order to simulate the unsteady interaction of the plate with the flow, a “liquid oscillator” model is used. Auto-oscillations arising in the system are studied. Dependence of their amplitude and frequency on the flow speed is analyzed.

Periodical motions of a hinge mechanism type wind power system

A wind power system based on an antiparallel link mechanism is proposed. Mathematical model is constructed. Sufficient conditions of existence of attractive periodical motions are derived using the Poincare-Pontryagin theorem. Asymptotic bifurcation diagrams are constructed. Trapped power at periodical motions is estimated.

On unstable periodic regime of small HAWT

Dynamics of a small HAWT is studied. The closed mathematical model involving phenomenological description of both aerodynamic load upon turbine blades and permanent magnet electric generator is developed, in order to take into account the inductive reactance of the electric circuit. A series of experiments is performed in the subsonic wind tunnel of the LMSU Institute of Mechanics that allowed verifying the model and identifying its parameters. Parameters of dynamic model are identified, such as the coefficient of electromechanical interaction, the active internal resistance of generator, the circuit reactance. Parametric analysis of steady regimes is performed. The model prediction that HAWT operating dynamic system has two stable steady regimes (high speed regime and low speed one) is confirmed by experiments. Transient regimes are registered depending on parameters of the system, which allows estimating the unstable steady regime. The characteristics of the unstable regime are experimentally determined...

Wind Car Driven by the Magnus Force

A mathematical model of a wind car is introduced. The car is equipped by the Magnus-type horizontal axis wind rotor. The shaft of the rotor is connected by a reduction gear with driving wheels of a vehicle. The wheels move without slipping along the line that is parallel to the wind flow. Steady motions of the vehicle are studied. It is shown that the vehicle can move upwind, as well as downwind faster than the wind. The speed of the vehicle is estimated depending on the transmission gear ratio. The maximal speed is compared with that obtained for different types of wind powered vehicles.

A Vehicle Driven Upwind by the Horizontal Axis Wind Turbine

A mathematical model of a wind powered vehicle is constructed. The vehicle is driven by a horizontal axis wind turbine. It is supposed that the velocity of the center of mass of the vehicle is directed upwind. Conditions of existence and stability of the steady upwind motion are discussed. The maximum speed of the upwind motion is estimated. The maximum speed is compared with that obtained for different types of wind powered vehicles.

On motion control of an aerodynamic pendulum

Problem of motion control of an aerodynamic pendulum is considered, when the control is aimed at bringing the pendulum to specified position in such a way as to avoid the aftereffect. The unsteady interaction between the pendulum and the flow is simulated using the attached oscillator model. It is shown that behavior of the aerodynamic pendulum under control law obtained using the conventional quasi-steady approach can differ from the target behavior, and the discrepancy increases as the moment of inertia of the pendulum gets larger.

Limit Cycle Oscillations of an Aerodynamic Pendulum

Dynamics of an aerodynamic pendulum in low-speed airflow is studied using the phenomenological model, where the internal dynamics of the flow is simulated using an oscillator attached to the pendulum. Limit cycle oscillations occurring in the vicinity of the “along the flow” equilibrium at a certain range of wind speeds are studied. Their evolution under changing system parameters (wind speed, holder length, etc.) is analyzed. Experimental study of such oscillations of the aerodynamic pendulum is performed in the subsonic wind tunnel of the Institute of Mechanics of Lomonosov Moscow State University for different wind speeds and different structural parameters of the pendulum. It is shown that results of experiments are in good enough agreement with simulation results.

Effect of nonlinear electromechanical interaction upon wind power generator behavior

A mathematical model is developed for describing a small horizontal axis wind turbine with electric generator, such that the electromechanical interaction is non-linear in current. Dependence of steady regimes of the system upon parameters of the model is studied. In particular, it is shown that increase of wind speed causes qualitative restructuring of the set of steady regimes, which leads to considerable change in behavior of the wind power generator. The proposed model is verified against data obtained in experiments.