Development of Axial Flows in Wake Vortices due to End Effects

AIAA Journal ◽  
2021 ◽  
pp. 1-18
Author(s):  
Gustavo Castaneda Fuentes ◽  
Frank Hüttmann ◽  
Sven Grundmann
Keyword(s):  
End Effects ◽  
Wake Vortices

Large eddy simulation of aircraft wake vortices within homogeneous turbulence - Crow instability

AIAA Journal ◽  
2000 ◽  
Vol 38 ◽  
pp. 292-300 ◽  
Author(s):  
Jongil Han ◽  
Yuh-Lang Lin ◽  
David G. Schowalter ◽  
S. P. Arya ◽  
Fred H. Proctor
Keyword(s):  
Large Eddy Simulation ◽  
Homogeneous Turbulence ◽  
Wake Vortices ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Aircraft Wake ◽  
Crow Instability

scholarly journals A Novel, Improved Equivalent Circuit Model for Double-Sided Linear Induction Motor

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1644
Author(s):  
Qian Zhang ◽  
Huijuan Liu ◽  
Tengfei Song ◽  
Zhenyang Zhang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Equivalent Circuit ◽  
Skin Effect ◽  
Equivalent Circuit Model ◽  
Element Model ◽  
Circuit Model ◽  
End Effects ◽  
3D Finite Element ◽  
Linear Induction

A novel, improved equivalent circuit model of double-sided linear induction motors (DLIMs) is proposed, which takes the skin effect and the nonzero leakage reactance of the secondary, longitudinal, and transverse end effects into consideration. Firstly, the traditional equivalent circuit with longitudinal and transverse end effects are briefly reviewed. Additionally, the correction coefficients for longitudinal and transverse end effects derived by one-dimensional analysis models are given. Secondly, correction factors for skin effect, which reflects the inhomogeneous air gap magnetic field vertically, and the secondary leakage reactance are derived by the quasi-two-dimensional analysis model. Then, the proposed equivalent circuit is presented, and the excitation reactance and secondary resistance are modified by the correction coefficients derived from the three analytical models. Finally, a three-dimensional (3D) finite element model is used to verify the proposed equivalent circuit model under varying air gap width and frequency, and the results are also compared with that of the traditional equivalent circuit models. The calculated thrust characteristics by the proposed equivalent circuit and 3D finite element model are experimentally validated under a constant voltage–frequency drive.

scholarly journals A new method of phase-shifting and displacement of unit motor to suppress the thrust fluctuation of linear motor

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110087
Author(s):  
Feng Zhou ◽  
Han Zhao ◽  
Xiaoke Liu ◽  
Fujia Wang
Keyword(s):  
Permanent Magnet ◽  
Linear Motor ◽  
Phase Shifting ◽  
New Method ◽  
Analysis Model ◽  
End Effects ◽  
Element Analysis ◽  
Suppression Effect ◽  
Permanent Magnet Linear Motor ◽  
Thrust Fluctuation

Permanent magnet linear motors can cause thrust fluctuation due to cogging and end effects, which will affect the operation stability of the linear motor. In order to solve this problem, a new method of eliminating alveolar force by using phase-shifting and displacement is proposed in this paper. Taking the cylindrical permanent magnet linear motor as an example, the traditional cylindrical permanent magnet linear motor is divided into two unit-motors, and established finite element analysis model of cylindrical permanent magnet linear motor. It is different from other traditional methods, the thrust fluctuation was reduced by both phase-shifting and displacement simultaneously in this paper, and through simulation analysis, it is determined that the thrust fluctuation suppression effect was the best when the cogging distance was shifted by half. Furthermore, a comparative simulation was made on whether the magnetic insulating material was used. The simulation results show that: The method proposed in this paper can effectively suppress the thrust fluctuation of the cylindrical permanent magnet linear motor. And it can be applied to other similar motor designs. Compared with the traditional method of suppressing thrust fluctuation, the mechanical structure and the technological process of suppressing thrust fluctuation used in this method are simpler.

Comparison of hydrodynamic performance and wake vortices of two typical types of pumpjet propulsor

2021 ◽  
Vol 224 ◽  
pp. 108700
Author(s):  
Denghui Qin ◽  
Qiaogao Huang ◽  
Yuejun Shi ◽  
Guang Pan ◽  
Yao Shi ◽  
...  
Keyword(s):  
Hydrodynamic Performance ◽  
Wake Vortices

scholarly journals A Matrix FMEA Analysis of Variable Delivery Vane Pumps

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1741
Author(s):  
Joanna Fabis-Domagala ◽  
Mariusz Domagala ◽  
Hassan Momeni
Keyword(s):  
Risk Analysis ◽  
Failure Modes ◽  
High Reliability ◽  
Matrix Analysis ◽  
Hydraulic Systems ◽  
Vane Pump ◽  
End Effects ◽  
Root Cause ◽  
Preventative Measures ◽  
Fmea Analysis

Hydraulic systems are widely used in the aeronautic, machinery, and energy industries. The functions that these systems perform require high reliability, which can be achieved by examining the causes of possible defects and failures and by taking appropriate preventative measures. One of the most popular methods used to achieve this goal is FMEA (Failure Modes and Effects Analysis), the foundations of which were developed and implemented in the early 1950s. It was systematized in the following years and practically implemented. It has also been standardized and implemented as one of the methods of the International Organization for Standardization (ISO) 9000 series standards on quality assurance and management. Apart from wide application, FMEA has a number of weaknesses, which undoubtedly include risk analysis based on the RPN (Risk Priority Number), which is evaluated as a product of severity, occurrence, and detection. In recent years, the risk analysis has been very often replaced by fuzzy logic. This study proposes the use of matrix analysis and statistical methods for performing simplified RCA (Root Cause Analysis) and for classification potential failures for a variable delivery vane pump. The presented methodology is an extension of matrix FMEA and allows for prioritizing potential failures and their causes in relation to functions performed by pump components, the end effects, and the defined symptoms of failure of the vane pump.

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