A method for obtaining depth estimates from the geometry of Slingram profiles

Geophysics ◽  
1991 ◽  
Vol 56 (10) ◽  
pp. 1543-1552 ◽  
Author(s):  
K. Duckworth ◽  
H. T. Calvert ◽  
J. Juigalli

An approximate method for deriving conductor depth estimates from the geometry of horizontal coplanar coil Slingram type electromagnetic profiles is based on a transformation of the recorded profile to a form which is free of the influence of coil separation. Depth estimates are derived from an empirically determined linear relationship between the spatial separation of maxima on the transformed profile and the depth of the conductor. Field examples and electromagnetic scale modelling indicate that the method works well on both thin and thick conductors with dips ranging from 90 to 60 degrees. Field examples and model results also show that the method works well when a conductive overburden is present, even if the overburden causes phase inversion. Examples of the application of the method show that while knowledge of the conductance of a target will aid in depth estimation, good depth estimates can be made even if the conductance of the target cannot be determined. Comparative scale model studies of conductors located first in free‐space and then in a conductive host suggest that the method will also give good results for targets located in conductive host rocks.

Author(s):  
Ryuichi Sato ◽  
Takayuki Mori ◽  
Ryo Yakushiji ◽  
Kenji Naganuma ◽  
Masaharu Nishimura ◽  
...  

The Flow Noise Simulator (FNS) of the 1st Research Center of TRDI/JDA (Japan Defense Agency) is a large, variable pressure, recirculating water tunnel with very low background noise level. The tunnel is 20m high and 49m long, containing 2000m3 of water. The test section has a square cross section of 2m × 2m with 10m in length. It will accept large size surface ship models of 6m, submarine models of 4m in length and full scale ship appendix models. The FNS is currently under construction and will be accomplished in 2005. It will be used for a wide variety of hydrodynamic and hydroacoustic testing of surface ships and submarines, such as propeller cavitation noise measurements and propeller-hull interaction observation, with sufficiently large scale models. Conceptual design of the FNS was started in 1996 and evaluated by following scale model studies. This paper discusses some technical issues of the FNS.


1985 ◽  
Vol 6 ◽  
pp. 48-52 ◽  
Author(s):  
Yutaka Anno

This paper presents a small scale modelling of a snowdrift using activated clay particles.Characteristic properties of activated clay particles, which are different from model snow particles proposed previously by other investigators, are fineness, high angle of repose and wide range of cohesion. Such properties may provide a similitude of a snowdrift and the phenomena caused by wet snow particles in a small scale model.Experimental results presented in this paper show that activated clay particles are the most suitable substitute for natural snow particles in modelling, and indicate also the possibility of using them to model wet snow particles.


2011 ◽  
Vol 18 (3-4) ◽  
pp. 259-280 ◽  
Author(s):  
Jens Holger Rindel

Today most acoustic consultants are using room acoustic computer models as a basis for their acoustic design. However, room acoustic scale modelling is still being used for the design in some major projects, although the costs and the time needed are significantly larger than those related to computer modelling. Both techniques were used by the author in a project for a new opera theatre; first the acoustical design was based on computer simulations using the Odeon software, and next a 1:20 scale model was built and tested. In the paper the results obtained with the two different modelling techniques are compared, and in general a satisfactory agreement has been found. The advantages and drawbacks related to each of the modelling techniques are discussed.


Author(s):  
Соснина ◽  
Olga Sosnina ◽  
Бирюкова ◽  
Alisa Biryukova

When working at an architectural or industrial project, it is generally required to make its prototype or scale model, which would accurately replicate the structure designed. Scale modelling permits locating errors and inaccuracies; it enhances spatial vision and promotes architectural thinking. Scale modelling also reveals new features of architectural objects that have already been created. "Nizhny Novgorod Cableway" serves as an example of such objects. The article describes the technology for designing a scale model of the cableway, which demonstrates an updated lighting system on its supports.


1976 ◽  
Vol 1 (15) ◽  
pp. 147 ◽  
Author(s):  
Charles K. Sollitt ◽  
Donald H. Debok

Large scale model studies reveal that Reynolds scaling can affect the apparent stability and wave modifying properties of layered breakwater structures. Results of a study for a breakwater configuration designed to protect offshore power and port facilities in water depths to 60 feet are presented and discussed. The armor layer of this structure is formed from quarried rock of irregular rectangular parallelepiped shape, individually placed perpendicular to 1:2 seaward slope and crest. The resulting armor layer is relatively smooth, densely packed and very stable. Model studies of similar configurations were studied at 1:10, 1:20 and 1:100 scale ratios. Stability, runup, rundown and reflection were measured for a variety of water depths, wave heights and periods. Analysis of the large scale test results establish that the placed stone armor is approximately as stable as dolos armor units. Runup, rundown and reflection respond similar to rough, impermeable slopes. Comparison of large and small scale results demonstrate that relative increases in drag forces at lower Reynolds numbers decrease stability and runup in small scale models.


2021 ◽  
Author(s):  
Xingyu Zhang ◽  
◽  
Matteo Ciantia ◽  
Jonathan Knappett ◽  
Anthony Leung ◽  
...  

When testing an 1:N geotechnical structure in the centrifuge, it is desirable to choose a large scale factor (N) that can fit the small-scale model in a model container and avoid unwanted boundary effects, however, this in turn may cause scale effects when the structure is overscaled. This is more significant when it comes to small-scale modelling of sinker root-soil interaction, where root-particle size ratio is much lower. In this study the Distinct Element Method (DEM) is used to investigate this problem. The sinker root of a model root system under axial loading was analysed, with both upward and downward behaviour compared with the Finite Element Method (FEM), where the soil is modelled as a continuum in which case particle-size effects are not taken into consideration. Based on the scaling law, with the same prototype scale and particle size distribution, different scale factors/g-levels were applied to quantify effects of the ratio of root diameter (𝑑𝑟) to mean particle size (𝐷50) on the root rootsoil interaction.


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