scholarly journals Object surface reconstruction from flow tracers

2021 ◽  
Vol 62 (2) ◽  
Author(s):  
Constantin Jux ◽  
Andrea Sciacchitano ◽  
Fulvio Scarano
Keyword(s):  
Theoretical Foundation ◽  
Synthetic Data ◽  
Fluid Flows ◽  
Object Surface ◽  
Solid Models ◽  
Tracer Distribution ◽  
Sharp Edges ◽  
Working Principle ◽  
Circle Diameter ◽  
Distribution Of Flow

Abstract A method to identify the surface of solid models immersed in fluid flows is devised that examines the spatial distribution of flow tracers. The fluid–solid interface is associated with the distance from the center of a circle to the centroid of the tracers ensemble captured within it. The theoretical foundation of the method is presented for 2D planar interfaces in the limit of a continuous tracer distribution. The discrete regime is analyzed, yielding the uncertainty of this estimator. Also the errors resulting from curved interfaces are discussed. The method's working principle is illustrated using synthetic data of a 2D cambered airfoil, showing that one of the limitations is the treatment of an object thinner than the search circle diameter. The method is readily adapted to 3D and applied to the 3D PTV data of the flow around a juncture. The surface is reconstructed within the expected uncertainty, and specific limitations, such as the smoothing of sharp edges is observed. Graphic abstract

Study on Kinematics Simulation of 3-TPT Parallel Machine Tool Based on Pro/E

2011 ◽  
Vol 199-200 ◽  
pp. 1555-1559 ◽  
Author(s):  
Heng Hua Zhao ◽  
Chuan Qiang Wang
Keyword(s):  
Machine Tool ◽  
Three Dimensional ◽  
Parallel Machine ◽  
Motion Simulation ◽  
Solid Models ◽  
Kinematics Simulation ◽  
Sense Of Reality ◽  
Working Principle ◽  
Simulation Results ◽  
Parallel Machine Tool

The machinery composition and working principle of 3-TPT parallel machine tool were analyzed. The three dimensional solid models of components of 3-TPT parallel machine tool were designed by using Pro/E. The virtual assembly and connection of the machine tool were accomplished in the assembly environment of Pro/E. Besides, the three-dimensional motion simulation of mechanism about the machine tool was researched in the mechanism module of Pro/E. The three-dimensional animation achieved by the simulation has the strong sense of reality. The working principle of the parallel machine tool was verified by the simulation. The simulation results show that the machine tool has advantages such as good stationarity, no interference and no singularity.

scholarly journals Trajectory encounter volume as a diagnostic of mixing potential in fluid flows

2017 ◽  
Vol 24 (2) ◽  
pp. 189-202 ◽  
Author(s):  
Irina I. Rypina ◽  
Lawrence J. Pratt
Keyword(s):  
Gulf Stream ◽  
Duffing Oscillator ◽  
Fluid Flows ◽  
Time Interval ◽  
Reference Trajectory ◽  
Strain Rates ◽  
Finite Time Interval ◽  
Linear Strain ◽  
Linear Shear ◽  
Tracer Distribution

Abstract. Fluid parcels can exchange water properties when coming into contact with each other, leading to mixing. The trajectory encounter mass and a related simplified quantity, the encounter volume, are introduced as a measure of the mixing potential of a flow. The encounter volume quantifies the volume of fluid that passes close to a reference trajectory over a finite time interval. Regions characterized by a low encounter volume, such as the cores of coherent eddies, have a low mixing potential, whereas turbulent or chaotic regions characterized by a large encounter volume have a high mixing potential. The encounter volume diagnostic is used to characterize the mixing potential in three flows of increasing complexity: the Duffing oscillator, the Bickley jet and the altimetry-based velocity in the Gulf Stream extension region. An additional example is presented in which the encounter volume is combined with the u∗ approach of Pratt et al. (2016) to characterize the mixing potential for a specific tracer distribution in the Bickley jet flow. Analytical relationships are derived that connect the encounter volume to the shear and strain rates for linear shear and linear strain flows, respectively. It is shown that in both flows the encounter volume is proportional to time.

The compact Platform for In Situ Nanoindentation and Scratch Test

2010 ◽  
Vol 97-101 ◽  
pp. 4342-4345
Author(s):  
Hu Huang ◽  
Hong Wei Zhao ◽  
Ji Qiang Deng ◽  
Zhi Chao Ma ◽  
Lei Lei Hu ◽  
...  
Keyword(s):  
Materials Science ◽  
Theoretical Foundation ◽  
Research Work ◽  
Scratch Test ◽  
Testing Platform ◽  
Displacement Sensors ◽  
Theoretical Significance ◽  
Working Principle ◽  
Precision Motion

A kind of experimental platform for in-situ nanoindentation and scratch test has been developed, which has high resolution of displacement and can be used to carry out nanoindentation and scratch test. The precision driven element composing of flexure hinges and piezoelectric actuator was analyzed, which was used to realize indenter’s precision motion. The components, working principle and performances of testing platform were introduced. The calibration experiments of loading and displacement sensors were carried out, and it showed loading and displacement sensors had high linearity and stability. The indentation experiments were carried out on a kind of glass. The experimental results showed proposed testing platform had good reproducibility and scheme was feasible. The research work will provide theoretical foundation and key technologies for nanomechanics test, and has theoretical significance and application value to materials science, micro-electronics, precision optics and biomechanics, etc.

scholarly journals Prospects for measuring Mercury’s tidal Love number h2 with the BepiColombo Laser Altimeter

2020 ◽  
Vol 633 ◽  
pp. A85 ◽  
Author(s):  
R. N. Thor ◽  
R. Kallenbach ◽  
U. R. Christensen ◽  
A. Stark ◽  
G. Steinbrügge ◽  
...  
Keyword(s):  
Inner Core ◽  
Thermal Evolution ◽  
Joint Inversion ◽  
Synthetic Data ◽  
Core Size ◽  
Love Number ◽  
Laser Altimetry ◽  
Laser Altimeter ◽  
Working Principle

Context. The Love number h2 describes the radial tidal displacements of Mercury’s surface and allows constraints to be set on the inner core size when combined with the potential Love number k2. Knowledge of Mercury’s inner core size is fundamental to gaining insights into the planet’s thermal evolution and dynamo working principle. The BepiColombo Laser Altimeter (BELA) is currently cruising to Mercury as part of the BepiColombo mission and once it is in orbit around Mercury, it will acquire precise measurements of the planet’s surface topography, potentially including variability that is due to tidal deformation. Aims. We use synthetic measurements acquired using BELA to assess how accurately Mercury’s tidal Love number h2 can be determined by laser altimetry. Methods. We generated realistic, synthetic BELA measurements, including instrument performance, orbit determination, as well as uncertainties in spacecraft attitude and Mercury’s libration. We then retrieved Mercury’s h2 and global topography from the synthetic data through a joint inversion. Results. Our results suggest that h2 can be determined with an absolute accuracy of ± 0.012, enabling a determination of Mercury’s inner core size to ± 150 km given the inner core is sufficiently large (>800 km). We also show that the uncertainty of h2 depends strongly on the assumed scaling behavior of the topography at small scales and on the periodic misalignment of the instrument.

Modeling and Simulation of Passive Dynamic Harmonic Filter Based on IGBT

2013 ◽  
Vol 475-476 ◽  
pp. 1615-1618
Author(s):  
Juan Li ◽  
Jing Chen ◽  
Yi Deng ◽  
Jing Li
Keyword(s):  
Power Supply ◽  
Power Supply System ◽  
Reactive Power ◽  
Theoretical Foundation ◽  
Industrial Applications ◽  
Supply System ◽  
Harmonic Suppression ◽  
Harmonic Filter ◽  
Working Principle ◽  
Simulation Results

The objective of this work is to simulate a kind of passive harmonic filter based on IGBT to improve the power factor of the power supply system, then to verify the feasibility of reactive power compensation and harmonic suppression. According to the topological structure and working principle of passive dynamic harmonic filter based on IGBT, the simulation model of the system has been set by the Simulink tool. Simulation results show that the passive dynamic harmonic filter based on IGBT can compensate the corresponding reactive power and suppress harmonic in the power grid. The research of this paper has laid a theoretical foundation for this filter in industrial applications.

Implementation of Shading Techniques Based on OpenGL

2014 ◽  
Vol 577 ◽  
pp. 1038-1042 ◽  
Author(s):  
Zheng Ju Wang ◽  
Ming Rui Chen
Keyword(s):  
Surface Brightness ◽  
Linear Interpolation ◽  
Object Surface ◽  
Sharp Edges

Shading can smooth the appearance of polygons by reducing the effects of sharp edges, which makes drawn graphics more realistic. Consider factors related to the object surface brightness, analyze and compare several shading algorithms, focus on presenting spherical linear interpolation of the Phong shading, and use OpenGL to realize the procedures and effect diagrams of Flat shading and Gouraud shading in VC + + environment.

The Parameter Performances and Simulations of Nitrogen-Inflating Hydraulic Breaker Based on AMESim

2014 ◽  
Vol 988 ◽  
pp. 625-629
Author(s):  
Yu Wan Cen ◽  
Liang Wu ◽  
Xiao Hua Ye ◽  
Ye Ye
Keyword(s):  
Flow Rate ◽  
Concrete Structure ◽  
Hydraulic System ◽  
Theoretical Foundation ◽  
Entire System ◽  
Pipe Length ◽  
Pressure Pipe ◽  
Pressure Feedback ◽  
Working Principle ◽  
At Home

After analyzing the technology of hydraulic breakers at home and abroad, this paper develops a new nitrogen-inflating hydraulic breaker based on the pressure feedback. Its concrete structure, the working principle and the hydraulic system are discussed. Then the entire system is built and simulated by using AMESim software. Impact performances are studied when some factors such as feedback pressure, pipe length and flow rate are changed. With all the achievements mentioned above, it provides a theoretical foundation for a further understanding of the hydraulic breaker.

scholarly journals Trajectory encounter number as a diagnostic of mixing potential in fluid flows

2016 ◽  
Author(s):  
Irina I. Rypina ◽  
Larry J. Pratt
Keyword(s):  
Gulf Stream ◽  
Duffing Oscillator ◽  
Fluid Flows ◽  
Time Interval ◽  
Reference Trajectory ◽  
Strain Rates ◽  
Linear Strain ◽  
Diffusive Regime ◽  
Linear Shear ◽  
Tracer Distribution

Abstract. Fluid parcels can exchange water properties when coming in contact with each other, leading to mixing. The trajectory encounter number, which quantifies the number of fluid parcel trajectories that pass close to a reference trajectory over a finite time interval, is introduced as a measure of the mixing potential of a flow. Regions characterized by low encounter numbers, such as cores of coherent eddies, have low mixing potential, whereas turbulent or chaotic regions characterized by large encounter numbers have high mixing potential. The encounter number diagnostic was used to characterize mixing potential in 3 flows of increasing complexity: the Duffing Oscillator, the Bickley Jet, and the altimetry-based velocity in the Gulf Stream Extension region. An additional example was presented where the encounter number was combined with the u-star-approach of Pratt et al., 2016 to characterize the mixing potential for a specific tracer distribution in the Bickley Jet flow. Analytical relationships were derived connecting encounter number to diffusivity for purely-diffusive flows, and to shear and strain rates for linear shear and linear strain flows, respectively. It is shown that in a diffusive regime the encounter number grows as a square-root of time, whereas in a linear shear and strain flows the encounter number is proportional to time.

Research on Multi-Fuze Co-Channel Interference Suppression Based on Pseudorandom Code Phase Modulation

2014 ◽  
Vol 539 ◽  
pp. 190-193
Author(s):  
Chuan Ting Wei ◽  
Quan Li Ning ◽  
Dong Chen
Keyword(s):  
Phase Modulation ◽  
Theoretical Foundation ◽  
Interference Suppression ◽  
Channel Interference ◽  
Working Principle

This paper introduces the working principle of the pseudorandom code phase modulation pulse, analyzes the theoretical foundation of multi-fuze co-channel interference suppression achieved by phase modulation of the signals through pseudorandom coding, and through the calculation and analysis of simulation, verifies the feasibility of the multi-fuze co-channel interference suppression based on pseudorandom code phase modulation.

Design and Dynamic Simulating Analysis of Planet Gear Mechanism of Cap Screwing Machine

2011 ◽  
Vol 411 ◽  
pp. 3-6
Author(s):  
Mei Ning Zhao ◽  
Jun Jie Gan ◽  
Fang Wang
Keyword(s):  
Rotational Speed ◽  
Theoretical Foundation ◽  
Simulation Software ◽  
Dynamics Simulation ◽  
Simulating Analysis ◽  
Planet Gear ◽  
Gear Mechanism ◽  
Working Principle

Planet gear mechanism is designed according to the planet gear action during the course of screw cap after working principle of the cap screwing machine is briefly introduced. The course of screw cap can be simulated by the dynamics simulation software ADAMS. The relation between rotational speed and the gearing-in force can be obtained. This provides the theoretical foundation for the improvement of seal quality in cap screwing machine.

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