Effects of partial fuel pump failure on center of gravity control for high-speed aircraft

2016 ◽  
Author(s):  
Haiquan Li ◽  
Jing Zhang ◽  
Jianing Yan
Keyword(s):  
High Speed ◽  
Center Of Gravity ◽  
Fuel Pump ◽  
Pump Failure

Angular Momentum Requirements of the Twisting and Nontwisting Forward 1 1/2 Somersault Dive

1987 ◽  
Vol 3 (1) ◽  
pp. 47-62 ◽  
Author(s):  
Ross H. Sanders ◽  
Barry D. Wilson
Keyword(s):  
Angular Momentum ◽  
High Speed ◽  
Center Of Gravity ◽  
Transverse Axis ◽  
Free Position ◽  
High Speed Cinematography ◽  
The Difference ◽  
Hip Flexion ◽  
Commonwealth Games

This study investigated the in-flight rotation of elite 3m springboard divers by determining the angular momentum requirement about the transverse axis through the divers center of gravity (somersault axis) required to perform a forward 1 1/2 somersault with and without twist. Three elite male divers competing in the 1982 Commonwealth Games were filmed using high-speed cinematography while performing the forward 1 1/2 somersault in the pike position and the forward 1 1/2 somersault with one twist in a free position. The film was digitized to provide a kinematic description of each dive. An inclined axis technique appeared to be the predominant means of producing twist after takeoff from the board. The angular momentum about the somersault axis after takeoff was greater for the forward 1 1/2 somersault with twist than the forward 1 1/2 somersault without twist for all three divers. The difference in angular momentum between the two dives of each diver ranged from 6% to 19%. The most observable difference between the dives during the preflight phases was the degree of hip flexion at takeoff. There was more hip flexion at takeoff in 5132D than 103B for all three divers. This difference ranged from 9° to 18° (mean = 14°).

Response Surface Models for Analyzing Planing Hull Motions in a Vertical Plane

2014 ◽  
Author(s):  
Tanvir Mehedi Sayeed ◽  
Leonard M. Lye ◽  
Heather Peng
Keyword(s):  
High Speed ◽  
Uniform Design ◽  
Vertical Plane ◽  
Statistical Design ◽  
Surrogate Models ◽  
Center Of Gravity ◽  
Design Parameters ◽  
Strip Theory ◽  
Calm Water ◽  
Sinkage And Trim

A non-linear mathematical model, Planing Hull Motion Program (PHMP) has been developed based on strip theory to predict the heave and pitch motions of planing hull at high speed in head seas. PHMP has been validated against published model test data. For various combinations of design parameters, PHMP can predict the heave and pitch motions and bow and center of gravity accelerations with reasonable accuracy at planing and semi-planing speeds. This paper illustrates an application of modern statistical design of experiment (DOE) methodology to develop simple surrogate models to assess planing hull motions in a vertical plane (surge, heave and pitch) in calm water and in head seas. Responses for running attitude (sinkage and trim) in calm water, and for heave and pitch motions and bow and center of gravity accelerations in head seas were obtained from PHMP based on a multifactor uniform design scheme. Regression surrogate models were developed for both calm water and in head seas for each of the relevant responses. Results showed that the simple one line regression models provided adequate fit to the generated responses and provided valuable insights into the behaviour of planing hull motions in a vertical plane. The simple surrogate models can be a quick and useful tool for the designers during the preliminary design stages.

Factors Contributing to Maximum Height of Dives after Takeoff from the 3M Springboard

1988 ◽  
Vol 4 (3) ◽  
pp. 231-259 ◽  
Author(s):  
Ross H. Sanders ◽  
Barry D. Wilson
Keyword(s):  
Vertical Velocity ◽  
Kinetic Data ◽  
High Speed ◽  
Mechanical Energy ◽  
Center Of Gravity ◽  
Whole Body ◽  
Maximum Height ◽  
Body Angle ◽  
High Speed Cinematography ◽  
Hip Flexion

This study investigated factors contributing to the maximum height achieved by divers after takeoff from the 3m springboard. Twelve elite male divers and 12 elite female divers competing in the 1986 Australian National Championships were filmed using high-speed cinematography. Kinematic and kinetic data for the takeoff phase were derived from the digitized film. Variables analyzed included center of gravity (CG) displacement and velocity, the acceleration of the CG relative to the springboard, and the components of mechanical energy contributing to height achieved by the diver’s CG. Body orientation was described in terms of the angles at the hip, knee, and ankle, and whole body angle of lean. Comparison of timing differences among dive groups and divers was aided by normalizing the data with respect to time. It was found that the height achieved was highly dependent on the rotational requirements of the dive, with males achieving greater heights than females. Divers who achieve good height compared to other divers performing the same dive are characterized by a large vertical velocity at touchdown from the hurdle and a minimization of hip flexion (forward dives) and knee flextion (reverse dives) at takeoff.

Paper 1: Computer Solution of Surge Problems

1965 ◽  
Vol 180 (5) ◽  
pp. 62-82
Author(s):  
Victor L. Streeter
Keyword(s):  
Steady State ◽  
Differential Equations ◽  
High Speed ◽  
Transient Flow ◽  
Nonlinear Differential Equations ◽  
Pressure Fluctuations ◽  
Transient Pressure ◽  
Pump Failure ◽  
Flow Equations ◽  
Flow Impedance

Methods for handling the transient flow equations are developed for application of the high-speed digital computer. For incompressible flow cases ordinary nonlinear differential equations occur which are solved simultaneously by established sub-routines on the computer, such as the Runge-Kutta method. For the partial differential equations of compressible water hammer with nonlinear terms such as friction, the method of characteristics and of specified time intervals are employed for those problems in which the flow changes from one steady-state to another steady-state. For steady-oscillatory flow, impedance methods have been adapted to the computer with harmonic analysis of the exciting disturbance. Experimental evidence is presented to confirm the accuracy of the procedures for single and series pipes, for pump failures, and for reciprocating pumps. Additionally the design problem of optimum operation of a valve to minimize transient pressure fluctuations has been introduced and applied to single and series pipes, including a pump failure situation.

Study on the Porpoising Phenomenon of High-Speed Trimaran Planing Craft

2018 ◽  
Author(s):  
Yuming Yuan ◽  
Chao Wang
Keyword(s):  
Fluid Dynamics ◽  
High Speed ◽  
Center Of Gravity ◽  
Rolling Motion ◽  
Upward Movement ◽  
Cfd Simulations ◽  
Flow Lines ◽  
Planing Craft ◽  
Computational Fluid Dynamics Cfd ◽  
Aerodynamic Lift

This paper presents the application of Computational Fluid Dynamics (CFD) simulations to the heaving and rolling motion of the planing craft under different speeds and centers of gravity. Comparing the flow lines, the pressure distribution at the bottom of the boat, the heave and the trim angle before instability with those elements after instability, a critical trim angle results in the early separation of the air in the bow. Meanwhile, due to effect of aerodynamic lift, the bow is lifted, which eventually leads to instability of the hull. Forward or upward movement of the center of gravity may eliminate or postpone the porpoising, the backward center of gravity may result in the unstablity of the ship. Serious porpoising is random and irregular. It will damage the structure of the hull, affect the maneuverability of the ship and threaten the safety of the crew.

Pulsed-neutron imaging by a high-speed camera and center-of-gravity processing

2018 ◽  
Vol 13 (01) ◽  
pp. C01038-C01038 ◽  
Author(s):  
K. Mochiki ◽  
T. Uragaki ◽  
J. Koide ◽  
Y. Kushima ◽  
J. Kawarabayashi ◽  
...  
Keyword(s):  
High Speed ◽  
Center Of Gravity ◽  
Neutron Imaging ◽  
High Speed Camera ◽  
Pulsed Neutron

scholarly journals A Turbine-Speed, Main-Engine Fuel Pump

1971 ◽  
Author(s):  
H. T. Johnson
Keyword(s):  
High Speed ◽  
Turbine Engines ◽  
Engine Fuel ◽  
Gas Turbine Engines ◽  
Fuel Flow Rate ◽  
Fuel Pump ◽  
Fuel Flow ◽  
Turbine Speed ◽  
Main Engine ◽  
Type Fuel

This paper describes the design and experimental evaluation of a vane-type fuel pump that has operated successfully at speeds up to 49,500 rpm and outlet pressures up to 900 psig. The objective of the research was to produce a main-engine fuel pump for small gas-turbine engines capable of operating at engine shaft speed in order to reduce the bulk and complexity of the required gear drive train. The pump has a design JP-4 turbine-fuel flow rate of 2000 lb/hr at 650 psig. The successful completion of a 200-hr endurance run has verified that the high-speed capabilities have been achieved without sacrificing pump endurance life.

Study on Visual Servosystems for Optical Microscopes to Observe a Moving Microorganism

2009 ◽  
Vol 3 (3) ◽  
pp. 348-354
Author(s):  
Hirotoshi Ibe ◽  
◽  
Jiro Otsuka ◽  
Hajime Onda ◽  
◽  
...  
Keyword(s):  
High Speed ◽  
Ccd Camera ◽  
Control Program ◽  
Optical Microscope ◽  
Center Of Gravity ◽  
Moving Object ◽  
Maximum Speed ◽  
Small Object

This paper describes a visual servosystem that observes a moving microorganism within the optical microscope view field. The visual servosystem consists of an optical microscope, a high-speed CCD camera, a controller, and XY stages. The camera takes an image every 4 milliseconds. The target’s center of gravity is calculated using inverse white-to-black processing and blocking processing. Its position is fed back to XY stages so that the target reaches the center of the view field. The control program is from LabVIEW. As a result, by means of this visual servosystem, the image of a very small object, for example, a kind of lobster of a size of 0.4 ∼ 0.6 mm which moves in the water at the maximum speed of 4 mm/s can be kept in view based on a method whereby, on the XY stages on which the moving object can continue to be observed.

ANALYSIS OF THE SPEED OF THE DEFUZZIFIER IN THE TASK OF CONTROLLING THE ROBOT-MANIPULATOR

2020 ◽  
pp. 18-28
Author(s):  
M. V. Bobyr ◽  
N. A. Milostnaya ◽  
A. E. Arkhipov ◽  
M. Yu. Luneva
Keyword(s):  
Simulation Model ◽  
Digital Filter ◽  
High Speed ◽  
Robot Manipulator ◽  
Computation Time ◽  
Robotic Manipulator ◽  
Center Of Gravity ◽  
Robotic Arm ◽  
Ratio Method ◽  
Gravity Method

Linear, nonlinear, modified, high-speed defuzzifiers based on the area ratio method are presented in this paper. The proposed defuzzifiers are used in a fuzzy digital filter device and make it possible to ensure the additivity of the robotic manipulator control system, since traditional models do not have this property. The essence of this development is to find a crisp value of the output fuzzy variable, which in this case are the regulation coefficients of the fuzzy digital filter. Reducing the number of computational operations provides an increase in the performance of the defuzzifier. The reduction in number of computational operations is carried out by eliminating the output variable’s truncated term’s height calculation, thereby reducing the computation time. A simulation model which was implemented in the MatLab Simulink system, for a neuro-fuzzy device of the robotic arm using linear and non-linear defuzzifiers is presented. The dependence of time graphs on the angle of rotation of the joints of the robotic manipulator are compared, based on the traditional center of gravity method and the method shown in this paper. It was found that the traditional center of gravity method does not ensure the fulfillment of the specified rotation angles of the links of the robotic arm, while the proposed models of defuzzifiers have this property, which can be seen from the presented dependency graphs. The simulation model of the device was also designed as a parallel-conveyor device for implementation in the field-programmable gate array of the Xilinx Spartan 3Е family. The analysis showed that the calculation time for a crisp value with high-speed defuzzification is 130 ns, which is two orders of magnitude higher than existing models. The experiment was conducted at a frequency of 100 MHz.

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