scholarly journals Research on the Undulatory Motion Mechanism of Seahorse Based on Dynamic Mesh

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Xinyu Quan ◽  
Ximing Zhao ◽  
Shijie Zhang ◽  
Jie Zhou ◽  
Nan Yu ◽  
...  
Keyword(s):  
Design Method ◽  
Fluid Dynamic ◽  
Underwater Vehicles ◽  
Dynamic Mesh ◽  
Driving Mechanism ◽  
Optimized Design ◽  
Motion Mechanism ◽  
Dorsal Fin ◽  
Propulsion Performance ◽  
Fluent Software

The seahorse relies on the undulatory motion of the dorsal fin to generate thrust, which makes it possess quite high maneuverability and efficiency, and due to its low volume of the dorsal fin, it is conducive to the study of miniaturization of the driving mechanism. This paper carried out a study on the undulatory motion mechanism of the seahorse’s dorsal fin and proposed a dynamic model of the interaction between the seahorse’s dorsal fin and seawater based on the hydrodynamic properties of seawater and the theory of fluid-structure coupling. A simulation model was established using the Fluent software, and the 3D fluid dynamic mesh was used to study the undulatory motion mechanism of the seahorse’s dorsal fin. The effect of the swing frequency, amplitude, and wavelength of the seahorse’s dorsal fin on its propulsion performance was studied. On this basis, an optimized design method was used to design a bionic seahorse’s dorsal fin undulatory motion mechanism. The paper has important guiding significance for the research and miniaturization of new underwater vehicles.

Optimization Research on Dynamic Balance of Spatial Engine under Limiting Shaking Moment

2009 ◽  
Vol 626-627 ◽  
pp. 693-698
Author(s):  
Yong Yong Zhu ◽  
S.Y. Gao
Keyword(s):  
Mathematical Model ◽  
Objective Function ◽  
Kinetic Analysis ◽  
Optimization Design ◽  
Design Method ◽  
Dynamic Balance ◽  
Optimized Design ◽  
Design Variables ◽  
The Mathematical Model ◽  
Shaking Moment

Dynamic balance of the spatial engine is researched. By considering the special wobble-plate engine as the model of spatial RRSSC linkages, design variables on the engine structure are confirmed based on the configuration characters and kinetic analysis of wobble-plate engine. In order to control the vibration of the engine frame and to decrease noise caused by the spatial engine, objective function is choosed as the dimensionless combinations of the various shaking forces and moments, the restriction condition of which presents limiting the percent of shaking moment. Then the optimization design is investigated by the mathematical model for dynamic balance. By use of the optimization design method to a type of wobble-plate engine, the optimization process as an example is demonstrated, it shows that the optimized design method benefits to control vibration and noise on the engines and improve the performance practically and theoretically.

Design and Analysis of Motion Mechanism Driven by Several IDMs in Parallel

2012 ◽  
Vol 197 ◽  
pp. 55-59 ◽  
Author(s):  
Nan Jiang ◽  
Jun Biao Liu
Keyword(s):  
Degrees Of Freedom ◽  
Design Method ◽  
Piezo Actuator ◽  
Motion Mechanism ◽  
Spherical Motor ◽  
Drive Mechanism ◽  
Follow Up Study ◽  
Analysis Of Motion

As a kind of piezo actuator, impact drive mechanism (IDM) has advantages in precision machinery and instruments. Several IDMs are used in parallel to realize some motion mechanisms which have multi degrees of freedom (DOF). Two motion mechanisms are designed subsequently, and a spherical motor is designed and assembled in principle based on one of them. Experiment results reveal that this design method is feasible, but some problems exist, for example, vibration is serious. These problems should be solved in follow-up study.

Comprehensive Design Method for Open or Ducted Propellers for Underwater Vehicles

2021 ◽  
Author(s):  
Spyros A. Kinnas ◽  
Kyungjung Cha ◽  
Seungnam Kim
Keyword(s):  
Design Method ◽  
A Priori ◽  
Optimization Method ◽  
Underwater Vehicles ◽  
Current Approach ◽  
Lattice Method ◽  
B Spline ◽  
Effective Wake ◽  
Propeller Thrust ◽  
Ducted Propellers

A comprehensive method which determines the most efficient propeller blade shapes for a given axisymmetric hull to travel at a desired speed, is presented. A nonlinear optimization method is used to design the blade, the shape of which is defined by a 3-D B-spline polygon, with the coordinates of the B-spline control points being the parameters to be optimized for maximum propeller efficiency, for given effective wake and propeller thrust. The performance of the propeller within the optimization scheme is assessed by a vortex-lattice method (VLM). To account fully for the hull/propeller interaction, the effective wake to the propeller and the hull resistance are determined by analyzing the designed propeller geometry by the VLM, coupled with a Reynolds-Averaged Navier-Stokes (RANS) solver. The optimization method re-designs the optimum blade with the updated effective wake and propeller thrust (taken to be equal to the updated hull resistance), and the procedure continues until convergence of the propeller performance. The current approach does not require knowledge of the wake fraction or the thrust deduction factor, both of which must be estimated a priori in traditional propeller design. The method is applied for a given hull to travel at a desired speed, and the optimum blades are designed for various combinations of propeller diameter and RPM, in the case of open and ducted propellers with provided duct shapes. The effects of the propeller diameter and RPM on the designed propeller thrust, torque, propeller efficiency, and required power are presented and compared with each other in the case of open and ducted propellers. The present approach is shown to provide guidance on the design of propulsors for underwater vehicles, and is applicable to the design of propulsors for surface ships.

scholarly journals Structure Optimization of UHV RIP Oil-SF6 bushings Based on Improved Equal Margin Design Method and Back-Propagation Neural Network

2021 ◽  
Vol 261 ◽  
pp. 03040
Author(s):  
Zhang Shiling
Keyword(s):  
Field Distribution ◽  
Optimization Design ◽  
Design Method ◽  
Back Propagation ◽  
Back Propagation Neural Network ◽  
Analytic Formula ◽  
Optimized Design ◽  
Thermal Coupling ◽  
Coupling Calculation ◽  
Temperature Factors

Equal margin design method based on the classic analytic formula is widely used in development of extra-high voltage bushing products, and its effectiveness and practicality have been fully validated. However, model and temperature factors have significant impact on internal E-field distribution of UHVAC and UHVDC bushing condenser, which traditional analytic formula is difficult to evaluate quantitatively, so it’s necessary to improve traditional equal margin design method. Firstly, basic principles of equal margin design method and its software package were briefly described, and the laws of model and temperature factors influencing on condenser E-field were investigated on FEM (finite element method) computing platform. Based on these, mathematical model of improved equal margin design method for bushing condenser was established, and flow chart of optimization process combining FEM electro-thermal coupling calculation with genetic algorithm was presented. The improved method was applied to design of UHV RIP oil-gas prototype to realize uniform axial E-field distribution along bushing condenser and equal partial discharge margin between adjacent foils. Bushing condenser was fabricated according to above optimized design structure, and has passed all type tests. In the paper, the FEM electro-thermal coupling calculation method was applied to the inner insulation optimization design to make bushing condenser’s design more suitable. The paper can provide some theoretical guidelines for research and development of other bushings in UHV level.

Mechanics Analysis and Optimized Design of Aircraft Skin Pass Damage Repair

2014 ◽  
Vol 945-949 ◽  
pp. 306-309
Author(s):  
Ting Jian Dong ◽  
Jin Chen ◽  
Hua Peng Ding
Keyword(s):  
Empirical Equation ◽  
Design Method ◽  
Mechanical Analysis ◽  
Critical Parameters ◽  
Optimized Design ◽  
Design Problems ◽  
Damage Repair ◽  
Skin Repair ◽  
Aircraft Skin ◽  
Airline Company

Against the sticking patch design problems of pass damage of aircraft skin repair, by using the calculation method of mechanical analysis, the stress analysis of pass damage is completed. The calculation methods are used quantitatively to determine the sticking patch dimension of pass damage repair, which is compared with analysis sticking patch design method calculated by the repair empirical equation of aircraft skin of Airline Company. The reason of error is analyzed and the measure to correct empirical equation method is put forward. The optimization of the critical parameters of pass damage empirical equation is completed.

An Approximate Three-Dimensional Aerodynamic Design Method for Centrifugal Impeller Blades

1990 ◽  
Vol 112 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Zhao Xiaolu ◽  
Qin Lisen
Keyword(s):  
Centrifugal Compressor ◽  
Design Method ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Design Procedure ◽  
Taylor Series Expansion ◽  
Centrifugal Impeller ◽  
Aerodynamic Design ◽  
Impeller Blade ◽  
Blade Geometry

An aerodynamic design method, which is based on the Mean Stream Surface Method (MSSM), has been developed for designing centrifugal compressor impeller blades. As a component of a CAD system for centrifugal compressor, it is convenient to use the presented method for generating impeller blade geometry, taking care of manufacturing as well as aerodynamic aspects. The design procedure starts with an S2m indirect solution. Afterward from the specified S2m surface, by the use of Taylor series expansion, the blade geometry is generated by straight-line elements to meet the manufacturing requirements. Simultaneously, the fluid dynamic quantities across the blade passage can be determined directly. In terms of these results, the designer can revise the distribution of angular momentum along the shroud and hub, which are associated with blade loading, to get satisfactory velocities along the blade surfaces in order to avoid or delay flow separation.

scholarly journals Numerical Investigation of Temperature Distribution in an Eroded Bend Pipe and Prediction of Erosion Reduced Thickness

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Hongjun Zhu ◽  
Guang Feng ◽  
Qijun Wang
Keyword(s):  
Temperature Distribution ◽  
Minimum Temperature ◽  
Fluid Dynamic ◽  
Temperature Drop ◽  
New Method ◽  
Inlet Temperature ◽  
Cfd Simulations ◽  
Bend Pipe ◽  
Severe Erosion ◽  
Fluent Software

Accurate prediction of erosion thickness is essential for pipe engineering. The objective of the present paper is to study the temperature distribution in an eroded bend pipe and find a new method to predict the erosion reduced thickness. Computational fluid dynamic (CFD) simulations with FLUENT software are carried out to investigate the temperature field. And effects of oil inlet rate, oil inlet temperature, and erosion reduced thickness are examined. The presence of erosion pit brings about the obvious fluctuation of temperature drop along the extrados of bend. And the minimum temperature drop presents at the most severe erosion point. Small inlet temperature or large inlet velocity can lead to small temperature drop, while shallow erosion pit causes great temperature drop. The dimensionless minimum temperature drop is analyzed and the fitting formula is obtained. Using the formula we can calculate the erosion reduced thickness, which is only needed to monitor the outer surface temperature of bend pipe. This new method can provide useful guidance for pipeline monitoring and replacement.

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