Feasability Studies for a Bionic Blimp with a Fish-Like Propulsion Systems (original) (raw)
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Many attempts have been made to mimic the movement of a fish in water in order to find novel solutions in autonomous underwater vehicles (AUV) . Conventional airships are driven by propellers and steered by stabilizers with rudders or with thrust vector control. Such propulsion and steering systems are efficient only in a small range of operation. The goal of our project is to mimic the fish-like movement with an airship body in air. In a theoretical study we have shown that a 6m long airship in air is similar to the trout in water. Therefore we want to build a geometrically similar body which mimics the body motion of a trout in steady state swimming. The activation is realized using Dielectric Elastomers (DE), a promising class of Electroactive Polymers (EAP). The principles of biomimetics in structural design and propulsion are discussed in this paper. The similarity of the optimized solutions found by the evolution for animals living in water and an optimized design of an airship will be shown. In a next step, the design of an indoor-flying airship propelled by a fish-like motion is evaluated. Various development tests, including wind tunnel testing and flight trials were performed and the gained results will be presented. First computational fluiddynamic simulations performed have shown similar vortex flow fields. In addition, the average forces could be measured accurately in wind tunnel tests and will be used to dimensioning the activation of the fin appropriately. From these results a conclusion shall be drawn, how far biomimetics can be used successfully in the design of future airship. Fin Ray Effect®
Biological Propulsion Systems for Ships and Underwater Vehicles
Propulsion Systems, 2019
Regulations and performance requirements related to technology development on all modes of transport vehicles for reduced pollution and environmental impact have become more stringent. Greening of transport system has been recognized as an important factor concerning global warming and climate change. Thus environment-friendly technical solutions offering a reduction of noxious exhaust gases are in demand. Aquatic animals have good swimming and maneuvering capabilities and these observations have motivated research on fish-like propulsion for marine vehicles. The fish fin movements, used by fish for their locomotion and positioning, are being replicated by researchers as flapping foils to mimic the biological system. Studies show that flapping foil propulsion systems are generally more efficient than a conventional screw propeller, which suffers efficiency losses due to wake. The flapping foil propulsors usually do not cavitate and have less wake velocity variation. These aspects result in the reduction of noise and vibration. The present study will cover an overview of aquatic propulsion systems, numerical simulations of flapping foils and ship model self-propulsion experiments performed using flapping foil system, particle image velocimetry (PIV), and digital fluoroscopy studies conducted on fish locomotion. Studies performed on underwater and surface vehicles fitted with flapping fins will also be presented.
Biologically-Inspired Water Propulsion System
Journal of Bionic Engineering, 2013
Most propulsion systems of vehicles travelling in the aquatic environment are equipped with propellers. Observations of nature, however, show that the absolute majority of organisms travel through water using wave motion, paddling or using water jet power. Inspired by these observations of nature, an innovative propulsion system working in aquatic environment was developed. This paper presents the design of the water propulsion system. Particular attention was paid to the use of paddling techniques and water jet power. A group of organisms that use those mechanisms to travel through water was selected and analysed. The results of research were used in the design of a propulsion system modelled simultaneously on two methods of movement in the aquatic environment. A method for modelling a propulsion system using a combination of the two solutions and the result were described. A conceptual design and a prototype constructed based on the solution were presented. With respect to the solution developed, studies and analyses of selected parameters of the prototype were described.
Study of the thrust–drag balance with a swimming robotic fish
Physics of Fluids, 2018
A robotic fish is used to test the validity of a simplification made in the context of fish locomotion. With this artificial aquatic swimmer, we verify that the momentum equation results from a simple balance between a thrust and a drag that can be treated independently in the small amplitude regime. The thrust produced by the flexible robot is proportional to A2f2, where A and f are the respective tail-beat amplitude and oscillation frequency, irrespective of whether or not f coincides with the resonant frequency of the fish. The drag is proportional to U02, where U0 is the swimming velocity. These three physical quantities set the value of the Strouhal number in this regime. For larger amplitudes, we found that the drag coefficient is not constant but increases quadratically with the fin amplitude. As a consequence, the achieved locomotion velocity decreases, or the Strouhal number increases, as a function of the fin amplitude.
Proceedings of the International Naval Engineering Conference and Exhibition (INEC)
Fish and other sea borne creatures have invoked interest in the minds of many professionals to study how they propel themselves in water and whether similar principles can be applied to the design of underwater vehicles. Adopting these principles for propulsion had been a challenge some decades ago, but with the current technological progress in robotics, design analysis, advanced computing, precision manufacturing, 3D printing, sensors, actuation, image processing etc have rekindled an interest in this field, especially in the Indian context. Moreover, with the thrust on development of unmanned autonomous systems, especially for the naval warfare, there is a case for looking at an efficient way to propel such vehicles that can stay underwater for a longer duration, move and navigate faster than those traditionally shaped and propelled by screw propellers or pump jets. This paper looks at some of the basics of fish locomotion; technology trends; examples of the current developments;...
Design Considerations for a Robotic Flying Fish
This paper details an exploration into the design of an aerial-aquatic robotic vessel. A compact robot that could both swim underwater and glide in the air above water has many potential applications in ocean exploration and mapping, surveillance, and forecasting. In the first phase of this project, we focus on mechanical design concepts that would enable the biomimetic production of adequate thrust underwater. A brief review of precedent research concerning robotic fish and hydrodynamics is first presented, followed by an in-depth analysis of the mathematical theory relevant to the project. A passive model of a flying fish was constructed and launched from approximately 1 ft. underwater to determine the forces associated with overcoming drag underwater and exiting the water. Based on this, A number of conceptual designs which would produce the motion necessary for propulsion were formulated and are discussed from a mechanical design perspective. Various conventional and nonconventional actuators are reviewed, as well as a control scheme for the concepts presented. We end with a discussion of the future directions for this project, as well as the key challenges that remain to be addressed.
Diversity, mechanics and performance of natural aquatic propulsors
Flow Phenomena in Nature, 2006
Both animals and engineered vehicles must contend with the same physical forces that dictate their performance during movement in water. Due to evolution, animals display a wide diversity of propulsive systems associated with swimming modes, body morphologies, and performance levels. Biologists have classified propulsive modes according to the animals' anatomy (e.g. axial, appendicular), kinematics (e.g. anguilliform, carangiform, thunniform), and propulsive forces (e.g. drag-based, lift-based, acceleration reaction). The various swimming modes are associated with different indices of performance (i.e. speed, acceleration, maneuverability) that are dependent on the ecology of the animal. High speed and high efficiency are associated with lift-based propulsion produced by oscillation of rigid, high-aspect ratio hydrofoils (i.e. thunniform mode). However, the propulsive systems and body morphology associated with high levels of acceleration and maneuverability diverge from systems designed for speed and efficiency. Drag-based systems, such as paddling, are relatively inefficient and used at low speeds but allow for precise maneuverability and generalized use of the propulsive appendages. In instances where energy economy is important, animals display behavioral mechanisms to extend range, increase swimming speed, and reduce energy costs. These behaviors include swimming in discrete formations (e.g. schooling, drafting), aerial leaps (e.g. porpoising), intermittent swimming (e.g. burst-andcoast), free-riding (e.g. wave and bow riding, hitchhiking), hydroplaning, and vorticity control. The evolution of aquatic animals has produced a great diversity of morphological designs and propulsive modes that can be exploited for biomimetic engineered systems. However, evolution is not a conscious process and is dictated by variation in the genetic code and multi-functional roles of animals in response to local environments. Strict application of biological systems into engineered systems without defining mission requirements may not produce optimal solution.
Hydrodynamics of Fishlike Swimming
Annual Review of Fluid Mechanics, 2000
Interest in novel forms of marine propulsion and maneuvering has sparked a number of studies on unsteadily operating propulsors. We review recent experimental and theoretical work identifying the principal mechanism for producing propulsive and transient forces in oscillating flexible bodies and fins in water, the formation and control of large-scale vortices. Connection with studies on live fish is made, explaining the observed outstanding fish agility. Annu. Rev. Fluid Mech. 2000.32:33-53. Downloaded from arjournals.annualreviews.org by UNIVERSITY OF MAINE -ORONO on 04/13/08. For personal use only. Annu. Rev. Fluid Mech. 2000.32:33-53. Downloaded from arjournals.annualreviews.org by UNIVERSITY OF MAINE -ORONO on 04/13/08. For personal use only. Annu. Rev. Fluid Mech. 2000.32:33-53. Downloaded from arjournals.annualreviews.org by UNIVERSITY OF MAINE -ORONO on 04/13/08. For personal use only.
Bioinspired Design Process for an Underwater Flying and Hovering Vehicle
2011
We review here the results obtained during the past several years in a series of computational and experimental investigations aimed at understanding the origin of high-force production in the flapping wings of insects and the flapping and deforming fins of fish and the incorporation of that information into bioinspired vehicle designs. We summarize the results obtained on pectoral fin force production, flapping and deforming fin design, and the emulation of fish pectoral fin swimming in unmanned vehicles. In particular, we discuss the main results from the computational investigations of pectoral fin force production for a particular coral reef fish, the bird wrasse (Gomphosus varius), whose impressive underwater flight and hovering performance matches our vehicle mission requirements. We describe the tradeoffs made between performance and produceability during the bio-inspired design of an actively controlled curvature pectoral fin and the incorporation of it into two underwater flight vehicles: a two-fin swimming version and four-fin swimming version. We describe the unique computational approach taken throughout the fin and vehicle design process for relating fin deformation time-histories to specified desired vehicle dynamic behaviors. We describe the development of the vehicle controller, including hardware implementation, using actuation of the multiple deforming flapping fins as the only means of propulsion and control. Finally, we review the comparisons made to date between four-fin vehicle experimental trajectory measurements and controller simulation predictions and discuss the incorporation of those comparisons into the controller design.
Swimming performance of a biomimetic compliant fish-like robot
Experiments in Fluids, 2009
Digital particle image velocimetry and fluorescent dye visualization are used to characterize the performance of fish-like swimming robots. During nominal swimming, these robots produce a ‘V’-shaped double wake, with two reverse-Kármán streets in the far wake. The Reynolds number based on swimming speed and body length is approximately 7500, and the Strouhal number based on flapping frequency, flapping amplitude, and swimming speed is 0.86. It is found that swimming speed scales with the strength and geometry of a composite wake, which is constructed by freezing each vortex at the location of its centroid at the time of shedding. Specifically, we find that swimming speed scales linearly with vortex circulation. Also, swimming speed scales linearly with flapping frequency and the width of the composite wake. The thrust produced by the swimming robot is estimated using a simple vortex dynamics model, and we find satisfactory agreement between this estimate and measurements made during static load tests.