5 research outputs found
Investigation of dual varying area flapping actuator of a robotic fish with energy recovery
Autonomous under-water vehicles (AUV) performing a commanded task require to
utilize on-board energy sources. At the time when on-board power source runs low during
operation, the vehicle (AUV) is forced to abort the mission and to return to a charging station.
The present work proposes the technique of an energy recovery from surrounding medium. This
effect is studied for dual action actuator movement that obtains energy from fluid. It is realized
that a flapping or vibrating actuator can be used for energy extraction phenomenon apart from the
non-traditional propulsive technique. In the present work a simple dual flapping actuator that can
switch between simple flat plate and perforated plate at extreme end positions (angles) by using
an efficient mechatronic mechanism that would help in overcoming viscous forces of the
operating medium is extensively studied. The main objective of the present article is to develop
a new approach for energy gain and recharge power pack of on-board sources from the
surrounding medium and to create a robotic fish that would work autonomously by using
unconventional drive along with the possibility of energy restoration by using dual varying area
type vibrating actuator. At the time of recharge, the robotic fish would project its tail (actuator)
out of water and use surrounding medium (air) to scavenge the energy. All the equations
describing the process are formed according to classical laws of mechanics. The mechatronic
system is explained and the results obtained are discussed in detail for air as the operating fluid
to scavenge energy
Analysis of non-stationary flow interaction with simple form objects
ArticleThe paper is devoted to the analysis of a non-stationary rigid body interaction in a fluid
flow. Initially, an approximate method for determining the forces due to fluid interaction with the
rigid body is offered. For this purpose, the plane movement of a mechanical system with an
infinite DOF (degrees of freedom) is reduced to 5 DOF motion: 3 DOF for the body and 2 DOF
for the areas of compression and vacuum in fluid flow. Differential equations of non-stationary
motion are formed by the laws of classical mechanics. The use of an approximate method has
been quantified by computer modelling. The average difference in results was found to be small
(< 5%). The analysis of the fluid (air) interaction is carried out for a rigid body of two simple
geometries - flat plate and diamond. The results obtained are used to refine the parameters of the
proposed approximate method that is addressed in the present study for fluid interaction with the
non-stationary rigid body. Theoretical results obtained in the final section are used in the analysis
of the movement of prismatic bodies in order to obtain energy from the fluid flow
Analysis of non-stationary flow interaction with simple form objects
ArticleThe paper is devoted to the analysis of a non-stationary rigid body interaction in a fluid
flow. Initially, an approximate method for determining the forces due to fluid interaction with the
rigid body is offered. For this purpose, the plane movement of a mechanical system with an
infinite DOF (degrees of freedom) is reduced to 5 DOF motion: 3 DOF for the body and 2 DOF
for the areas of compression and vacuum in fluid flow. Differential equations of non-stationary
motion are formed by the laws of classical mechanics. The use of an approximate method has
been quantified by computer modelling. The average difference in results was found to be small
(< 5%). The analysis of the fluid (air) interaction is carried out for a rigid body of two simple
geometries - flat plate and diamond. The results obtained are used to refine the parameters of the
proposed approximate method that is addressed in the present study for fluid interaction with the
non-stationary rigid body. Theoretical results obtained in the final section are used in the analysis
of the movement of prismatic bodies in order to obtain energy from the fluid flow
Optimization of Energy Extraction Using Definite Geometry Prisms in Airflow
An approximate method for analysis and synthesis of moving rigid bodies (prisms) in the airflow without using numerical methods of space-time programming techniques is described by applying a fluid (air)–rigid solid body interaction concept for engineering applications through a straightforward mathematical model. The interaction of rigid body (prism) and air is encountered in different cases: moving body (prism) in the air; stationary bodies (prism) in the airflow; moving body (prism) in the airflow. The complicated task of rigid body (prism) and air interaction is simplified by using superposition principles, i.e., by taking into account the upstream and downstream rigid body (prism) and air interaction phenomenon, which has been found to be different under varying speeds. Numerical results obtained for various forms of prisms are shown for constant air–speed, where the steady state Reynolds-averaged Navier–Stokes (RANS) equation is solved by using k-ε realizable turbulence model. A detailed explanation to support the proposed approximate method is given by using numerical results obtained in ANSYS computations. All equations are formed based on laws of classical mechanics; the interaction of viscous forces is neglected in forming the mathematical model. Numerical results for different model prisms are compared and the theoretical results discussed in detail. The mathematical model in the present paper is applicable only to bodies that undergo a rectilinear translation motion. In the final part of the present paper, the proposed method is used in the synthesis and optimization task of energy extraction by considering the motion of a variable parameter prism in the airflow