Borehole Propagation With Undergaged Stabilizers: Theory and Validation

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Umut Zalluhoglu ◽  
Julien Marck ◽  
Hossam Gharib ◽  
Yiming Zhao
Keyword(s):  
Field Test ◽  
Test Data ◽  
Three Dimensional ◽  
Propagation Model ◽  
Test Surface ◽  
Propagation Modeling ◽  
Proposed Model ◽  
Delayed System ◽  
Actual Field

This paper discusses borehole propagation modeling in the drilling industry. A three-dimensional (3D) borehole propagation model is proposed that tracks the wellbore/stabilizer contacts caused by an overgaged borehole. The resulting model represents a nonlinear delayed system that can be efficiently used to simulate borehole propagation. Simulations are provided to show the model capabilities to capture various drilling scenarios. The predictions are also validated with actual field-test data from mud-motor and rotary-steerable operations. The proposed model can be used to (a) design mud motors and rotary steerable systems (RSSs) and evaluate their steering performance, (b) design and test surface and downhole controllers for wellplan tracking, and (c) provide predictive recommendations to help directional driller operators make steering decisions while drilling.

scholarly journals Hearables: feasibility of recording cardiac rhythms from head and in-ear locations

2017 ◽  
Vol 4 (11) ◽  
pp. 171214 ◽  
Author(s):  
Wilhelm von Rosenberg ◽  
Theerasak Chanwimalueang ◽  
Valentin Goverdovsky ◽  
Nicholas S. Peters ◽  
Christos Papavassiliou ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Vital Signs ◽  
Propagation Model ◽  
Mobile Technologies ◽  
Neural Signals ◽  
Future Health ◽  
Characteristic P ◽  
Proposed Model ◽  
Head Surface ◽  
Electric Potentials

Mobile technologies for the recording of vital signs and neural signals are envisaged to underpin the operation of future health services. For practical purposes, unobtrusive devices are favoured, such as those embedded in a helmet or incorporated onto an earplug. However, these locations have so far been underexplored, as the comparably narrow neck impedes the propagation of vital signals from the torso to the head surface. To establish the principles behind electrocardiogram (ECG) recordings from head and ear locations, we first introduce a realistic three-dimensional biophysics model for the propagation of cardiac electric potentials to the head surface, which demonstrates the feasibility of head-ECG recordings. Next, the proposed biophysics propagation model is verified over comprehensive real-world experiments based on head- and in-ear-ECG measurements. It is shown both that the proposed model is an excellent match for the recordings, and that the quality of head- and ear-ECG is sufficient for a reliable identification of the timing and shape of the characteristic P-, Q-, R-, S- and T-waves within the cardiac cycle. This opens up a range of new possibilities in the identification and management of heart conditions, such as myocardial infarction and atrial fibrillation, based on 24/7 continuous in-ear measurements. The study therefore paves the way for the incorporation of the cardiac modality into future ‘hearables’, unobtrusive devices for health monitoring.

scholarly journals Three-Dimensional Vehicle-to-Vehicle Channel Modeling with Multiple Moving Scatterers

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Derong Du ◽  
Xiaoping Zeng ◽  
Xin Jian ◽  
Lijuan Miao ◽  
Haobo Wang
Keyword(s):  
Correlation Functions ◽  
Three Dimensional ◽  
Channel Modeling ◽  
Multipath Fading ◽  
Time Correlation ◽  
Propagation Model ◽  
Time Correlation Functions ◽  
Vehicle To Vehicle ◽  
Proposed Model ◽  
Special Cases

Connected vehicles have received much attention in recent years due to their significant societal benefit and commercial value. However, a suitable channel model for vehicle-to-vehicle (V2V) communications is difficult to build due to the dynamic communication environment. In this paper, a three-dimensional (3D) geometrical propagation model that includes line-of-sight (LoS), single bounced (SB), and multiple bounced (MB) rays is proposed. Each of multiple scatterers in the model is moving with a random velocity in a random direction. Based on the geometrical propagation model, a generalized 3D reference model for narrowband multiple-input-multiple-output (MIMO) V2V multipath fading channels is developed. The corresponding space-time correlation functions (ST-CFs), time correlation functions (T-CFs), and space correlation functions (S-CFs) are analytically investigated and numerically simulated in terms of various factors. Several notable ST-CFs for V2V and fixed-to-mobile (F2M) communications become the special cases of ST-CFs of the proposed model by adjusting the corresponding channel parameters. Finally, the theoretical results of the space-Doppler power spectral density (SD-PSD) are compared with the available measured data. The close agreements between the theoretical and measured SD-PSD curves confirm the utility and generality of the proposed model.

Simulation of a Vehicle Impacting a Modified Thrie-Beam Guardrail

1997 ◽  
Vol 1599 (1) ◽  
pp. 1-10 ◽  
Author(s):  
C. A. Plaxico ◽  
R. M. Hackett ◽  
W. Uddin
Keyword(s):  
Finite Element ◽  
Field Test ◽  
Simulation Study ◽  
Three Dimensional ◽  
Crash Test ◽  
Test Program ◽  
Element Simulation ◽  
Dimensional Finite Element ◽  
Actual Field ◽  
Three Dimensional Finite Element

A three-dimensional finite-element simulation study, developed for the purpose of modeling the event of a compact automobile impacting a modified thrie-beam guardrail, is presented. The developed computational model has been used to simulate an actual field test that was previously conducted as part of a full-scale crash test program carried out under the auspices of FHWA. Results of the actual crash test are also used to "tune" the simulation model.

Laboratory Slurry Erosion Tests and Pump Wear Rate Calculations

1984 ◽  
Vol 106 (2) ◽  
pp. 135-140 ◽  
Author(s):  
J. J. Tuzson
Keyword(s):  
Wear Rate ◽  
Flow Pattern ◽  
Field Test ◽  
Test Data ◽  
Three Dimensional ◽  
Numerical Verification ◽  
Slurry Erosion ◽  
Pump Impeller ◽  
Erosion Model ◽  
Order Of Magnitude

From order-of-magnitude calculations, the erosion mechanism in slurry pumps for mining applications was found to be a scouring type. Impact erosion was found to be unlikely to occur. The erosion model assumes a “sliding bed” type of flow pattern and neglects the effect of turbulent diffusion of slurry particles. This choice was based on flow regime data from slurry pipeline flow and was not verified experimentally in pumps. A new centrifugal-erosion laboratory testing fixture was designed and fabricated at Allis-Chalmers which reproduces this type of erosion. Since flow conditions were closely controlled, an absolute rate of erosion could be determined. For mild steel (Rockwell C = 10) and aluminum oxide particles, a specific erosion energy of 1.5 × 108 in-lb/in3 (1000 joules/mm3) was measured. Flow pattern and slurry concentrations were calculated in a pump impeller using a quasi-three-dimensional streamline curvature method. These were combined with the above erosion model and the local erosion rate was estimated. Actual operating data had to be estimated for a quarry application of the pump because field test data was not available. The uncertainties of the field test data did not allow an exact numerical verification of the wear rate calculation, but order of magnitude agreement was obtained. The wear rate distribution agreed very well with the wear pattern observed on the impeller used in the quarry and the locations of excessive wear could be identified.

Study on the generalized k-Hilfer–Prabhakar fractional viscoelastic–plastic model

2021 ◽  
pp. 108128652110258
Author(s):  
Yi-Ying Feng ◽  
Xiao-Jun Yang ◽  
Jian-Gen Liu ◽  
Zhan-Qing Chen
Keyword(s):  
Constitutive Model ◽  
Three Dimensional ◽  
Sensitivity Analyses ◽  
Creep Process ◽  
Fractional Operator ◽  
Modified Model ◽  
Proposed Model ◽  
Accelerated Creep ◽  
The Laplace Transform ◽  
Classical Models

The general fractional operator shows its great predominance in the construction of constitutive model owing to its agility in choosing the embedded parameters. A generalized fractional viscoelastic–plastic constitutive model with the sense of the k-Hilfer–Prabhakar ( k-H-P) fractional operator, which has the character recovering the known classical models from the proposed model, is established in this article. In order to describe the damage in the creep process, a time-varying elastic element [Formula: see text] is used in the proposed model with better representation of accelerated creep stage. According to the theory of the kinematics of deformation and the Laplace transform, the creep constitutive equation and the strain of the modified model are established and obtained. The validity and rationality of the proposed model are identified by fitting with the experimental data. Finally, the influences of the fractional derivative order [Formula: see text] and parameter k on the creep process are investigated through the sensitivity analyses with two- and three-dimensional plots.

scholarly journals System Identification of Alfred Zampa Memorial Bridge Using Dynamic Field Test Data

2009 ◽  
Vol 135 (1) ◽  
pp. 54-66 ◽  
Author(s):  
Xianfei He ◽  
Babak Moaveni ◽  
Joel P. Conte ◽  
Ahmed Elgamal ◽  
Sami F. Masri
Keyword(s):  
System Identification ◽  
Field Test ◽  
Test Data ◽  
Dynamic Field

Effects of Wheel-Shaft-Fluid Coupling and Local Wheel Deformations on the Global Behavior of Shaft Lines

2002 ◽  
Vol 124 (4) ◽  
pp. 953-957 ◽  
Author(s):  
D. Lornage ◽  
E. Chatelet ◽  
G. Jacquet-Richardet
Keyword(s):  
Three Dimensional ◽  
Fluid Film ◽  
Global Behavior ◽  
Three Dimensional Model ◽  
Fluid Films ◽  
Strongly Coupled ◽  
Proposed Model ◽  
Structural Deformations ◽  
Time Marching ◽  
Fluid Coupling

Rotating parts of turbomachines are generally studied using different uncoupled approaches. For example, the dynamic behavior of shafts and wheels are considered independently and the influence of the surrounding fluid is often taken into account in an approximate way. These approaches, while often sufficiently accurate, are questionable when wheel-shaft coupling is observed or when fluid elements are strongly coupled with local structural deformations (leakage flow between wheel and casing, fluid bearings mounted on a thin-walled shaft, etc.). The approach proposed is a step toward a global model of shaft lines. The whole flexible wheel-shaft assembly and the influence of specific fluid film elements are considered in a fully three-dimensional model. In this paper, the proposed model is first presented and then applied to a simple disk-shaft assembly coupled with a fluid film clustered between the disk and a rigid casing. The finite element method is used together with a modal reduction for the structural analysis. As thin fluid films are considered, the Reynolds equation is solved using finite differences in order to obtain the pressure field. Data are transferred between structural and fluid meshes using a general method based on an interfacing grid concept. The equations governing the whole system are solved within a time-marching procedure. The results obtained show significant influence of specific three-dimensional features such as disk-shaft coupling and local disk deformations on global behavior.

ACOUSTIC THREE-DIMENSIONAL EFFECTS AROUND THE TAIWAN STRAIT: COMPUTATIONAL RESULTS

1999 ◽  
Vol 07 (01) ◽  
pp. 15-26 ◽  
Author(s):  
CHI-FANG CHEN ◽  
JANG-JIA LIN ◽  
DING LEE
Keyword(s):  
Field Data ◽  
Bottom Topography ◽  
Three Dimensional ◽  
Propagation Model ◽  
Computational Results ◽  
Submarine Canyons ◽  
Offshore Area ◽  
Ocean Environment ◽  
The Taiwan Strait ◽  
Good Agreement

A set of experiments were performed in the offshore area off the coasts of Taiwan and three-dimensional (3-D) measurements recorded. The 3-D effect on underwater propagation due to azimuthal variation of bottom topography is studied for the offshore regions southwest of Taiwan, where submarine canyons exist. A 3-D acoustic propagation model, FOR3D, is used to detect the 3-D effect. Computational results show that the 3-D effect is more prominent along the axis of the canyon than across it. Calculations show a very good agreement with field data, which indicate that the 3-D effect exists in this realistic ocean environment.

A Greenwood-Williamson Model of Small-Scale Friction

2005 ◽  
Vol 74 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Reese E. Jones
Keyword(s):  
Numerical Method ◽  
Recursion Formula ◽  
Three Dimensional ◽  
Interfacial Friction ◽  
Small Scale ◽  
Analytical Estimate ◽  
Normal Loading ◽  
Proposed Model ◽  
Loading Case ◽  
Transition Length

A Greenwood and Williamson based model for interfacial friction is presented that incorporates the presliding transition phenomenon that can significantly affect small devices. This work builds on previous similar models by developing: an analytical estimate of the transition length in terms of material and surface parameters, a general recursion formula for the case of slip in one direction with multiple reversals and constant normal loading, and a numerical method for the general three-dimensional loading case. In addition, the proposed model is developed within a plasticity-like framework and is shown to have qualitative similarities with published experimental observations. A number of model problems illustrate the response of the proposed model to various loading conditions.

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