scholarly journals Benchmark Sea Trials on a 6-Meter Boat Powered by Kite

2020 ◽  
Vol 10 (18) ◽  
pp. 6148
Author(s):  
Kostia Roncin ◽  
Morgan Behrel ◽  
Paul Iachkine ◽  
Jean-Baptiste Leroux
Keyword(s):  
High Resolution ◽  
Power Law ◽  
Measurement System ◽  
Averaging Method ◽  
Wind Measurement ◽  
Phase Averaging

This paper presents sea trials on a 6-m boat specifically designed for kite propulsion. The kite control was automatic or manual, dynamic or static, depending on the point of sailing. The measurement system recorded boat motion and load generated by the kite. A particular attention was paid to wind measurement with several fixed and mobile locations directly on the kiteboat or in the vicinity. A high resolution weather modelling showed that a classical power law, describing the wind gradient, was not satisfactory to get the wind at kite location. 5-min measurement phases were systematically recorded. In the end, 101 runs were carried out. Data were processed with the phase-averaging method in order to produce reliable and accurate results.

scholarly journals High-Resolution Atmospheric Sensing of Multiple Atmospheric Variables Using the DataHawk Small Airborne Measurement System

2013 ◽  
Vol 30 (10) ◽  
pp. 2352-2366 ◽  
Author(s):  
Dale A. Lawrence ◽  
Ben B. Balsley
Keyword(s):  
High Resolution ◽  
Measurement System ◽  
Current System ◽  
Low Cost ◽  
Structure Constant ◽  
Turbulence Structure ◽  
Quality Of Data ◽  
Airborne Measurement ◽  
Atmospheric Measurement ◽  
Atmospheric Variables

Abstract The DataHawk small airborne measurement system provides in situ atmospheric measurement capabilities for documenting scales as small as 1 m and can access reasonably large volumes in and above the atmospheric boundary layer at low cost. The design of the DataHawk system is described, beginning with the atmospheric measurement requirements, and articulating five key challenges that any practical measurement system must overcome. The resulting characteristics of the airborne and ground support components of the DataHawk system are outlined, along with its deployment, operating, and recovery modes. Typical results are presented to illustrate the types and quality of data provided by the current system, as well as the need for more of these finescale measurements. Particular focus is given to the DataHawk's ability to make very-high-resolution measurements of a variety of atmospheric variables simultaneously, with emphasis given to the measurement of two important finescale turbulence parameters, (the temperature turbulence structure constant) and ɛ (the turbulent energy dissipation rate). Future sensing possibilities and limitations using this approach are also discussed.

GPU-based pseudo-transient finite difference solution for power-law viscous flow in cartesian, polar and spherical coordinates

2021 ◽  
Author(s):  
Emilie Macherel ◽  
Yuri Podladchikov ◽  
Ludovic Räss ◽  
Stefan M. Schmalholz
Keyword(s):  
High Resolution ◽  
Finite Difference ◽  
Viscous Flow ◽  
Power Law ◽  
High Performance ◽  
Viscoelastic Behavior ◽  
Iterative Solution ◽  
Circular Inclusion ◽  
Lithospheric Flexure ◽  
Gpu Architectures

<p>Power-law viscous flow describes well the first-order features of long-term lithosphere deformation. Due to the ellipticity of the Earth, the lithosphere is mechanically analogous to a shell, characterized by a double curvature. The mechanical characteristics of a shell are fundamentally different to the characteristics of plates, having no curvature in their undeformed state. The systematic quantification of the magnitude and the spatiotemporal distribution of strain, strain-rate and stress inside a deforming lithospheric shell is thus of major importance: stress is for example a key physical quantity that controls geodynamic processes such as metamorphic reactions, decompression melting, lithospheric flexure, subduction initiation or earthquakes.</p><p>Stress calculations in a geometrically and mechanically heterogeneous 3-D lithospheric shell require high-resolution and high-performance computing. The pseudo-transient finite difference (PTFD) method recently enabled efficient simulations of high-resolution 3-D deformation processes, implementing an iterative implicit solution strategy of the governing equations for power-law viscous flow. Main challenges for the PTFD method is to guarantee convergence, minimize the required iteration count and speed-up the iterations.</p><p>Here, we present PTFD simulations for simple mechanically heterogeneous (weak circular inclusion) incompressible 2-D power-law viscous flow in cartesian and cylindrical coordinates. The flow laws employ a pseudo-viscoelastic behavior to optimize the iterative solution by exploiting the fundamental characteristics of viscoelastic wave propagation.</p><p>The developed PTFD algorithm executes in parallel on CPUs and GPUs. The development was done in Matlab (mathworks.com), then translated into the Julia language (julialang.org), and finally made compatible for parallel GPU architectures using the ParallelStencil.jl package (https://github.com/omlins/ParallelStencil.jl). We may unveil preliminary results for 3-D spherical configurations including gravity-controlled lithospheric stress distributions around continental plateaus.</p>

scholarly journals Development of a High-Resolution Underwater Gravity Measurement System Installed on an Autonomous Underwater Vehicle

2018 ◽  
Vol 15 (12) ◽  
pp. 1937-1941 ◽  
Author(s):  
Masanao Shinohara ◽  
Toshihiko Kanazawa ◽  
Hiromi Fujimoto ◽  
Takemi Ishihara ◽  
Tomoaki Yamada ◽  
...  
Keyword(s):  
High Resolution ◽  
Measurement System ◽  
Autonomous Underwater Vehicle ◽  
Underwater Vehicle ◽  
Gravity Measurement

Design and test of laser wind measurement system for yaw control of wind turbine

2020 ◽  
Vol 49 (8) ◽  
pp. 20200228-20200228
Author(s):  
蒋杉 Shan Jiang ◽  
孙东松 Dongsong Sun ◽  
韩飞 Fei Han ◽  
熊丹枫 Danfeng Xiong ◽  
刘栋材 Dongcai Liu ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Measurement System ◽  
Wind Measurement ◽  
Yaw Control

scholarly journals Discovery of a New X-ray Transient in Scorpius GRO J1655-40 ≡ X-ray Nova Scorpii 1994

1996 ◽  
Vol 165 ◽  
pp. 363-367
Author(s):  
W.S. Paciesas ◽  
S.N. Zhang ◽  
B.C. Rubin ◽  
B.A. Harmon ◽  
C.A. Wilson ◽  
...  
Keyword(s):  
Black Hole ◽  
High Resolution ◽  
Power Law ◽  
Radio Observations ◽  
X Ray ◽  
Black Hole Candidate ◽  
Radio Jets ◽  
Transient Source ◽  
Galactic Source ◽  
Photon Index

A bright transient X-ray source, GRO J1655-40 (X-ray Nova Scorpii 1994) was discovered with BATSE (the Burst and Transient Source Experiment) in late July 1994. More recently, the source also became a strong radio emitter, its rise in the radio being approximately anti-correlated with a decline in the hard X-ray intensity. High-resolution radio observations subsequent to this symposium showed evidence for superluminally expanding jets. Since the hard X-ray emission extends to at least 200 keV and we find no evidence of pulsations, we tentatively classify the source as a black-hole candidate. However, its hard X-ray spectrum is unusually steep (power-law photon index α ≃ −3) relative to most other black-hole candidates. In this regard, it resembles GRS 1915+105, the first galactic source to show superluminal radio jets.

scholarly journals Wavelet-based analysis and power law classification of C/NOFS high-resolution electron density data

Radio Science ◽  
2014 ◽  
Vol 49 (8) ◽  
pp. 680-688 ◽  
Author(s):  
C. L. Rino ◽  
C. S. Carrano ◽  
Patrick Roddy
Keyword(s):  
High Resolution ◽  
Electron Density ◽  
Power Law ◽  
Density Data ◽  
Resolution Electron

Errors and Uncertainties in Microwave Link Rainfall Estimation Explored Using Drop Size Measurements and High-Resolution Radar Data

2010 ◽  
Vol 11 (6) ◽  
pp. 1330-1344 ◽  
Author(s):  
Hidde Leijnse ◽  
Remko Uijlenhoet ◽  
Alexis Berne
Keyword(s):  
High Resolution ◽  
Power Law ◽  
Radar Data ◽  
Mean Bias Error ◽  
Bias Error ◽  
Error Statistics ◽  
Link Length ◽  
Taylor’S Hypothesis ◽  
High Resolution Radar ◽  
Microwave Link

Abstract Microwave links can be used for the estimation of path-averaged rainfall by using either the path-integrated attenuation or the difference in attenuation of two signals with different frequencies and/or polarizations. Link signals have been simulated using measured time series of raindrop size distributions (DSDs) over a period of nearly 2 yr, in combination with wind velocity data and Taylor’s hypothesis. For this purpose, Taylor’s hypothesis has been tested using more than 1.5 yr of high-resolution radar data. In terms of correlation between spatial and temporal profiles of rainfall intensities, the validity of Taylor’s hypothesis quickly decreases with distance. However, in terms of error statistics, the hypothesis is seen to hold up to distances of at least 10 km. Errors and uncertainties (mean bias error and root-mean-square error, respectively) in microwave link rainfall estimates due to spatial DSD variation are at a minimum at frequencies (and frequency combinations) where the power-law relation for the conversion to rainfall intensity is close to linear. Errors generally increase with link length, whereas uncertainties decrease because of the decrease of scatter about the retrieval relations because of averaging of spatially variable DSDs for longer links. The exponent of power-law rainfall retrieval relations can explain a large part of the variation in both bias and uncertainty, which means that the order of magnitude of these error statistics can be predicted from the value of this exponent, regardless of the link length.

Sign in / Sign up

Export Citation Format

Share Document