scholarly journals Aerodynamic Characterization of an Off-the-Shelf Aircraft via Flight Test and Numerical Simulation

2016 ◽  
Author(s):  
Murat Bronz ◽  
Gautier Hattenberger
Keyword(s):  
Numerical Simulation ◽  
Flight Test

Measurements of real non-Newtonian response for liquid lubricants under moderate pressures

2001 ◽  
Vol 215 (3) ◽  
pp. 223-233 ◽  
Author(s):  
S Bair
Keyword(s):  
Numerical Simulation ◽  
Kinetic Theory ◽  
Simple Shear ◽  
Pressure Dependence ◽  
Shear Stresses ◽  
Current Interest ◽  
Flow Properties ◽  
Power Law Fluid ◽  
Temperature And Pressure

A thorough characterization of all viscous flow properties relevant to steady simple shear was carried out for five liquid lubricants of current interest to tribology. Shear stresses were generated to values significant to concentrated contact lubrication. Two types of non-Newtonian response were observed: shear-thinning as a power-law fluid and near rate-independence. Functions and parameters were obtained for the temperature and pressure dependence of the viscosity and of the time constant for the Carreau-Yasuda equation. Results are consistent with free volume and kinetic theory, but directly contradict many assumptions currently utilized for numerical simulation and for extracting rheological properties from contact measurements.

Dynamic Characterization of a Valveless Micropump Considering Entrapped Gas Bubbles

2013 ◽  
Vol 135 (9) ◽  
Author(s):  
Songjing Li ◽  
Jixiao Liu ◽  
Dan Jiang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Model ◽  
Experimental Studies ◽  
Gas Bubbles ◽  
Chamber Pressure ◽  
Dynamic Characterization ◽  
Valveless Micropump ◽  
Performance Deterioration ◽  
Trapped Gas

Unexpected gas bubbles in microfluidic devices always bring the problems of clogging, performance deterioration, and even device functional failure. For this reason, the aim of this paper is to study the characterization variation of a valveless micropump under different existence conditions of gas bubbles based on a theoretical modeling, numerical simulation, and experiment. In the theoretical model, we couple the vibration of piezoelectric diaphragm, the pressure drop of the nozzle/diffuser and the compressibility of working liquid when gas bubbles are entrapped. To validate the theoretical model, numerical simulation and experimental studies are carried out to investigate the variation of the pump chamber pressure influenced by the gas bubbles. Based on the numerical simulation and the experimental data, the outlet flow rates of the micropump with different size of trapped gas bubbles are calculated and compared, which suggests the influence of the gas bubbles on the dynamic characterization of the valveless micropump.

Numerical Simulation of Offshore Pipeline Installation by Lateral Deflection Procedure

2007 ◽  
Author(s):  
Danilo Machado Lawinscky da Silva ◽  
Rodrigo Almeida Bahiense ◽  
Breno Pinheriro Jacob ◽  
Fernando Gomes da Silva Torres ◽  
Antonio Roberto Medeiros ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Computational Tool ◽  
Lateral Deflection ◽  
Correct Definition ◽  
Offshore Pipeline ◽  
Definition Of

Conventional offshore pipeline installation operations in Brazil have been performed in an S-Lay procedure employing the BGL-1 barge, owned by Petrobras. However, this procedure has some limits, and may not be feasible in some particular scenarios. Therefore, the objective of this work is to present the numerical simulation of an alternative pipeline installation procedure. This procedure basically consists of performing the pipeline assembly on shore, and deflecting it to the sea using a tug boat. The numerical simulations employ the SITUA-Prosim computational tool, which is able to incorporate the correct definition of the seabed and shore from bathymetric curves. An actual pipeline installation by this lateral deflection procedure is analyzed and discussed. The characterization of the procedure passes through the determination of the better velocity and direction of the tug boat in order to minimize the efforts on the pipeline (especially due to the curvatures).

Analysis and simulation of a new Cartesian cable-suspended robot

2009 ◽  
Vol 224 (8) ◽  
pp. 1717-1726 ◽  
Author(s):  
G Castelli ◽  
E Ottaviano ◽  
A González
Keyword(s):  
Numerical Simulation ◽  
Degrees Of Freedom ◽  
Robot Arm ◽  
Fixed Frame ◽  
Cartesian Space ◽  
Compliant Assembly ◽  
Moving Platform ◽  
Geometry Analysis ◽  
Three Degrees Of Freedom

In this article, a manipulator is presented belonging to the class of cable-suspended robots, for which the cable length variations are related by suitable functions in order to achieve specific kinematic characteristics. In particular, in this article, a Cartesian cable-suspended robot is proposed that has eight cables to have three degrees of freedom (DOF) in Cartesian space. The eight cables of the robot are arranged in parallel by pairs with identical length, with the aim of constraining the moving platform to keep a constant orientation with respect to the fixed frame. The robot can be used for selective compliant assembly robot arm (SCARA) motions (when an additional revolute actuated joint is placed on the moving platform) for a variety of applications in which a large workspace is required. In this article, a geometry analysis of the robot is presented together with a numerical simulation of the kinetostatics and dynamics to investigate the robot's performances in several operative conditions. Furthermore, a characterization of the position workspace regions is reported for this cable-suspended robot.

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