Angular oscillations of solid bodies with a two-layer liquid near the main resonance

Trudy MAI ◽  
2021 ◽  
Author(s):  
Ko Ko Win ◽  
Alexander Temnov
Keyword(s):  
Main Resonance ◽  
Angular Oscillations ◽  
Solid Bodies

THE INFLUENCE OF SURFACE ROUGHNESS ON SCATTERING OF FREE-MOLECULAR FLOW BY SOLID BODIES

2016 ◽  
Vol 47 (4) ◽  
pp. 367-388 ◽  
Author(s):  
Alexander Ivanovich Erofeev ◽  
Alexander Petrovich Nikiforov ◽  
Sergei Borisovich Nesterov ◽  
Ramul'ya Amirovna Nezhmetdinova
Keyword(s):  
Surface Roughness ◽  
Molecular Flow ◽  
Free Molecular Flow ◽  
Solid Bodies

scholarly journals A Model for Performance Estimation of Flapping Foil Operating as Biomimetic Stream Energy Device

2020 ◽  
Vol 9 (1) ◽  
pp. 21
Author(s):  
Iro E. Malefaki ◽  
Kostas A. Belibassakis
Keyword(s):  
Vertical Axis ◽  
Flow Speed ◽  
Performance Estimation ◽  
Speed Ratio ◽  
Power Extraction ◽  
Flapping Foil ◽  
Flow Energy ◽  
Novel Concept ◽  
Angular Oscillations ◽  
Energy Converters

During the recent period intensive research has focused on the advancement of engineering and technology aspects concerning the development and optimization of wave and current energy converters driven by the need to increase the percentage of marine renewable sources in the energy-production mix, particularly from offshore installations. Most stream energy-harvesting devices are based on hydro-turbines, and their performance is dependent on the ratio of the blade-tip speed to incident-flow speed. As the oncoming speed of natural-occurring currents varies randomly, there is a penalty for the latter device’s performance when operating at non-constant tip-speed ratio away from the design value. Unlike conventional turbines that are characterized by a single degree of freedom rotating around an axis, a novel concept is examined concerning hydrokinetic energy converters based on oscillating hydrofoils. The biomimetic device includes a rotating, vertically mounted, biomimetic wing, supported by an arm linked at a pivot point on the mid-chord. Activated by a controllable self-pitching motion the system performs angular oscillations around the vertical axis in incoming flow. In this work, the performance of the above flapping-foil, biomimetic flow energy harvester is investigated by application of a semi-3D model based on unsteady hydrofoil theory and the results are verified by comparison to experimental data and a 3D boundary element method based on vortex rings. By systematical application of the model the power extraction and efficiency of the system is presented for various cases including different geometric, mechanical, and kinematic parameters, and the optimal performance of the system is determined.

Interaction of solid bodies with atmospheres of protoplanets

2018 ◽  
Vol 14 (S345) ◽  
pp. 351-352
Author(s):  
Ernst A. Dorfi ◽  
Florian Ragossnig
Keyword(s):  
Kinetic Energy ◽  
Physical Properties ◽  
Planet Formation ◽  
Frictional Heating ◽  
Protoplanetary Disk ◽  
Small Bodies ◽  
Early Stages ◽  
Break Up ◽  
Solid Bodies ◽  
Stellar Source

AbstractDuring the early stages of planet formation accretion of small bodies add mass to the planet and deposit their energy kinetic energy. Caused by frictional heating and/or large stagnation pressures within the dense and extended atmospheres most of the in-falling bodies get destroyed by melting or break-up before they impact on the planet’s surface. The energy is added to the atmospheric layers rather than heating the planet directly. These processes can significantly alter the physical properties of protoplanets before they are exposed with their primordial atmospheres to the early stellar source when the protoplanetary disk becomes evaporated.

scholarly journals Application of the erosion algorithm in modeling of structures behavior under impulse loads

2019 ◽  
Vol 221 ◽  
pp. 01003
Author(s):  
Pavel Radchenko ◽  
Stanislav Batuev ◽  
Andrey Radchenko
Keyword(s):  
Finite Element ◽  
High Velocity ◽  
Three Dimensional ◽  
Computer Software ◽  
Dynamic Loads ◽  
Complex Structures ◽  
Numerical Studies ◽  
Contact Surfaces ◽  
Fracture Of Materials ◽  
Solid Bodies

The paper presents results of applying approach to simulation of contact surfaces fracture under high velocity interaction of solid bodies. The algorithm of erosion -the algorithm of elements removing, of new surface building and of mass distribution after elements fracture at contact boundaries is consider. The results of coordinated experimental and numerical studies of fracture of materials under impact are given. Authors own finite element computer software program EFES, allowing to simulate a three-dimensional setting behavior of complex structures under dynamic loads, has been used for the calculations.

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