Supercavitating Vehicle Dynamics With Non-Cylindrical, Non-Symmetric Cavities

2007 ◽  
Author(s):  
Vincent Nguyen ◽  
Balakumar Balachandran ◽  
Abraham N. Varghese
Keyword(s):  
System Dynamics ◽  
Nonlinear Behavior ◽  
Force Model ◽  
Supercavitating Vehicles ◽  
Supercavitating Vehicle ◽  
Highly Nonlinear ◽  
Dynamics And Control ◽  
Cylindrical Cavities ◽  
Wall Interaction ◽  
And Control

Dive-plane dynamics of supercavitating vehicles show highly nonlinear behavior. This is attributed to the vehicle/cavity wall interaction, and the cavity shape has been recognized to play an important role in the system dynamics. To date, supercavitating models make use of constant cylindrical cavities. In this work, a dive-plane model with non-cylindrical and nonsymmetric cavity shapes is considered. A numeric cavity model is used, the cavitator angle of attack effects are considered, and a non-steady non-cylindrical planing force model is incorporated. The resulting effects on the system dynamics and control are addressed and discussed.

Supercavitating Vehicles With Noncylindrical, Nonsymmetric Cavities: Dynamics and Instabilities

2011 ◽  
Vol 6 (4) ◽  
Author(s):  
Vincent Nguyen ◽  
Balakumar Balachandran
Keyword(s):  
System Dynamics ◽  
Control Strategies ◽  
Critical Role ◽  
Vehicle Stability ◽  
Force Model ◽  
Plane Model ◽  
Supercavitating Vehicles ◽  
Supercavitating Vehicle ◽  
Vehicle System ◽  
Cylindrical Cavities

Cavity-wall interactions play an important role in determining the dynamics of supercavitating vehicles. To date, supercavitating vehicle system models make use of constant cylindrical cavities. As a further step, in this work, a dive-plane model with noncylindrical and nonsymmetric cavity shapes is developed. Cavitator angle of attack effects are considered, and a noncylindrical planing force model is incorporated. The system dynamics is examined in terms of nonlinear instabilities and the tail-slap phenomenon, and it is shown that the cavity shape plays a critical role in determining the system dynamics. The effectiveness of feedback control strategies with fin and cavitator inputs to achieve vehicle stability is also discussed.

Non-Steady Planing and Advection Delay Effects on the Dynamics and Control of Supercavitating Vehicles

2011 ◽  
Author(s):  
Vincent Nguyen ◽  
Munther A. Hassouneh ◽  
Balakumar Balachandran ◽  
Eyad H. Abed
Keyword(s):  
Vehicle Dynamics ◽  
Underwater Vehicles ◽  
Cavitation Number ◽  
Delay Effect ◽  
Supercavitating Vehicles ◽  
Supercavitating Vehicle ◽  
Delay Effects ◽  
Dynamics And Control ◽  
Position And Orientation ◽  
And Control

Cavity-vehicle interactions play a significant role in the dynamics of supercavitating underwater vehicles. To date, in the vast majority of planing force models for supercavitating vehicle dynamics, a steady planing assumption is utilized, wherein the vehicle-cavity interaction is only dependent on the vehicle’s position relative to the cavity. In this work, a framework to properly account for the vehicle radial motions into and out of the fluid is presented. This effectively introduces damping or velocity related dependence into the planing force formulation. The planing force is applied to cavity sections that are described by a previous (or delayed) position and orientation of the cavitator. The physical basis for the advection delay and the expressions used to determine the vehicle immersion and immersion rate are presented. Analysis and simulations for the time-delayed, non-steady planing system are carried out, and the delay effect in this system is shown to be stabilizing for certain values of the cavitation number that is contrary to previous results that have assumed steady planing force models.

scholarly journals Use of Cranes in Education and International Collaborations

2011 ◽  
Vol 23 (5) ◽  
pp. 881-892 ◽  
Author(s):  
William Singhose ◽  
◽  
Joshua Vaughan ◽  
Kelvin Chen Chih Peng ◽  
Brice Pridgen ◽  
...  
Keyword(s):  
System Dynamics ◽  
International Collaboration ◽  
Research Collaboration ◽  
Undergraduate Research ◽  
Program Assessment ◽  
The Internet ◽  
International Collaborations ◽  
The World ◽  
Dynamics And Control ◽  
And Control

This paper describes the use of cranes in system dynamics and control courses and international collaboration. Four different cranes designed and built for educational purposes are presented, and the curriculum developed to use the cranes is summarized. The cranes can be operated remotely from anywhere in the world via the Internet. This feature facilitates both educational activities and research collaboration. Example use of cranes in international collaboration and undergraduate research are described. The paper concludes with a discussion of key challenges and a program assessment.

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