Simulation of the Hydrodynamic Interaction Forces in Close-Proximity Manoeuvring

2008 ◽  
Author(s):  
Serge Sutulo ◽  
C. Guedes Soares
Keyword(s):  
Real Time ◽  
Hydrodynamic Interaction ◽  
Moving Objects ◽  
Time Derivative ◽  
Kirchhoff Equations ◽  
Interaction Forces ◽  
Acceptable Accuracy ◽  
Close Proximity ◽  
Added Masses ◽  
Real Time Simulations

A code for simulating hydrodynamic interaction forces in manoeuvring simulating systems has been created. The algorithm takes into account potential forces only and is based on the Hess and Smith panel method. Own inertial hydrodynamic forces were estimated through pre-calculation of the added masses followed by use of the Thomson–Tait–Kirchhoff equations. Comparative computations of the added masses, surge and sway interaction forces and yaw interaction moments with varying number of surface computational panels showed that on a typical modern PC, an acceptable accuracy in terms of the integrated loads can be reached with a relatively small number of panels permitting real-time simulations with the developed algorithm in the loop. Importance of the account for the local time derivative of the potential has been demonstrated on comparative calculations in simulation of a passing-by manoeuvre. The code can be used for predicting interaction loads with any number of moving objects and fixed obstacles.

Hydrodynamic Interaction Forces on Ship Hulls Equipped With Propulsors

2012 ◽  
Author(s):  
Serge Sutulo ◽  
C. Guedes Soares
Keyword(s):  
Pressure Distribution ◽  
Hydrodynamic Interaction ◽  
Potential Interaction ◽  
Interaction Forces ◽  
Ship Hulls ◽  
Actuator Disk ◽  
Close Proximity ◽  
Body Potential ◽  
Yaw Moment ◽  
Accelerating Motion

Typically, study of hydrodynamic interaction between vessels navigating in close proximity to each other is limited to hydrodynamics of bare hulls. Meanwhile, ship propulsors, especially heavily loaded, which may happen in accelerating motion, can alter substantially the flow and distribution of pressure on the hulls which can be viewed as generalization of the thrust deduction phenomenon. The 3D doubled body potential interaction code based on the source panel method developed earlier by the authors has been enhanced to include the effect of a propeller on each of the interacting ships under the assumption that the propeller jets (slipstreams) are not involved into the interaction. Each propeller is simulated by a disk of sinks further approximated with a polygon composed of identical triangular panels with identical constant sink density linked to the thrust of the propulsor according to the actuator disk theory. Comparative computations were carried out for two identical tanker vessels in the close-proximity overtaking manoeuvre at various values of the loading coefficient of each propeller. The loading coefficient is not supposed to be necessarily defined by the steady propulsion point. Numerical results demonstrate that a heavily loaded propeller substantially modifies the pressure distribution on both hulls resulting in alteration of the hydrodynamic interaction loads, especially of the surge force and yaw moment.

Computation of Ship-to-Ship Interaction Forces by a 3D Potential Flow Panel Method in Finite Water Depth

2010 ◽  
Author(s):  
Xueqian Zhou ◽  
Serge Sutulo ◽  
C. Guedes Soares
Keyword(s):  
Water Depth ◽  
Potential Flow ◽  
Hydrodynamic Interaction ◽  
Single Layer ◽  
Mirror Image ◽  
Present Contribution ◽  
Interaction Forces ◽  
Sea Bottom ◽  
Close Proximity ◽  
Finite Water Depth

The double-body 3D potential flow code developed earlier for computing hydrodynamic interaction forces and moments acting on the hulls of the ships sailing in close proximity with neighbouring ships or some other obstacles, is extended to the shallow water case. Two methods for accounting for the finite water depth were implemented: use of truncated mirror image series, and distribution of an additional single layer of sources on parts of the seabed beneath the moving hulls. While the first method does only apply to the flat horizontal seabed, the second one can also deal with the arbitrary bathymetry situations. As appropriate choice of the discretization parameters can significantly affect the accuracy and efficiency of the second method, the present contribution focuses on comparative computations aiming at defining reasonable dimensions of the moving panelled area on the sea bottom and maximum admissible size of the bottom panel. As result, conclusions concerning optimal parameters of the additional set of panels are drawn.

scholarly journals INTERACTIVE DYNAMIC SIMULATOR FOR MULTIBODY SYSTEMS

2012 ◽  
Vol 09 (03) ◽  
pp. 1250021 ◽  
Author(s):  
JEAN-RÉMY CHARDONNET
Keyword(s):  
Real Time ◽  
Multibody Systems ◽  
General Framework ◽  
Humanoid Robot ◽  
Humanoid Robots ◽  
Physical Models ◽  
Interaction Forces ◽  
Dynamic Simulator ◽  
Real Time Simulations ◽  
Interactive Dynamic

We propose an interactive dynamic simulator for humanoid robots using constraint-based methods for computing interaction forces with friction. This simulator is a part of a general framework for prototyping called AMELIF and is a successful integration of physical models. We focus on optimizing the computation of the dynamics to obtain real-time simulations allowing multimodal interactivity. Our simulator has been validated in two ways: first by comparing real sensors' measures and simulated values, then through different scenarios of complex manipulation tasks on the HRP-2 humanoid robot, bringing new insights to interactive robotics.

Real-Time Moving Objects Tracking for Distributed Smart Video Surveillances

2016 ◽  
Vol 11 (4) ◽  
pp. 324
Author(s):  
Nor Nadirah Abdul Aziz ◽  
Yasir Mohd Mustafah ◽  
Amelia Wong Azman ◽  
Amir Akramin Shafie ◽  
Muhammad Izad Yusoff ◽  
...  
Keyword(s):  
Real Time ◽  
Moving Objects ◽  
Objects Tracking

scholarly journals ATCO radar training assessment and flight efficiency: the correlation between trainees’ scores and fuel consumption in real-time simulations

2020 ◽  
pp. 1-17
Author(s):  
T. Rogošić ◽  
B. Juričić ◽  
F. Aybek Çetek ◽  
Z. Kaplan
Keyword(s):  
Real Time ◽  
Fuel Consumption ◽  
Basic Training ◽  
Air Traffic Controller ◽  
Training Assessment ◽  
Assessment Scores ◽  
Human In The Loop ◽  
Assessment Standards ◽  
Two Parameters ◽  
Real Time Simulations

ABSTRACT Air traffic controller training is highly regulated but lacks prescribed common assessment criteria and methods to evaluate trainees at the level of basic training and consideration of how trainees in fluence flight efficiency. We investigated whether there is a correlation between two parameters, viz. the trainees’ assessment score and fuel consumption, obtained and calculated after real-time human-in-the-loop radar simulations within the ATCOSIMA project. Although basic training assessment standards emphasise safety indicators, it was expected that trainees with higher assessment scores would achieve better flight efficiency, i.e. less fuel consumption. However, the results showed that trainees’ assessment scores and fuel consumption did not correlate in the expected way, leading to several conclusions.

scholarly journals Diagnostics and Prognostics of Energy Conversion Processes via Knowledge-Based Systems

Proceedings ◽  
2020 ◽  
Vol 58 (1) ◽  
pp. 1
Author(s):  
Roberto Melli ◽  
Enrico Sciubba
Keyword(s):  
Expert System ◽  
Knowledge Base ◽  
Real Time ◽  
System Analysis ◽  
Intelligent System ◽  
Time Derivative ◽  
Time History ◽  
Control Procedure ◽  
Time Data ◽  
Ongoing Research

This paper presents a critical and analytical description of an ongoing research program aimed at the implementation of an expert system capable of monitoring, through an Intelligent Health Control procedure, the instantaneous performance of a cogeneration plant. The expert system is implemented in the CLIPS environment and is denominated PROMISA as the acronym for Prognostic Module for Intelligent System Analysis. It generates, in real time and in a form directly useful to the plant manager, information on the existence and severity of faults, forecasts on the future time history of both detected and likely faults, and suggestions on how to control the problem. The expert procedure, working where and if necessary with the support of a process simulator, derives from the available real-time data a list of selected performance indicators for each plant component. For a set of faults, pre-defined with the help of the plant operator (Domain Expert), proper rules are defined in order to establish whether the component is working correctly; in several instances, since one single failure (symptom) can originate from more than one fault (cause), complex sets of rules expressing the combination of multiple indices have been introduced in the knowledge base as well. Creeping faults are detected by analyzing the trend of the variation of an indicator over a pre-assigned interval of time. Whenever the value of this ‘‘discrete time derivative’’ becomes ‘‘high’’ with respect to a specified limit value, a ‘‘latent creeping fault’’ condition is prognosticated. The expert system architecture is based on an object-oriented paradigm. The knowledge base (facts and rules) is clustered—the chunks of knowledge pertain to individual components. A graphic user interface (GUI) allows the user to interrogate PROMISA about its rules, procedures, classes and objects, and about its inference path. The paper also presents the results of some simulation tests.

scholarly journals Broccoli Fluorets: Split Aptamers as a User-Friendly Fluorescent Toolkit for Dynamic RNA Nanotechnology

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3178 ◽  
Author(s):  
Morgan Chandler ◽  
Tatiana Lyalina ◽  
Justin Halman ◽  
Lauren Rackley ◽  
Lauren Lee ◽  
...  
Keyword(s):  
Real Time ◽  
Logic Gates ◽  
Rna Aptamers ◽  
One Pot ◽  
Rna Nanotechnology ◽  
Close Proximity ◽  
Direct Tracking ◽  
Displacement Approach ◽  
User Friendly ◽  
In Cells

RNA aptamers selected to bind fluorophores and activate their fluorescence offer a simple and modular way to visualize native RNAs in cells. Split aptamers which are inactive until the halves are brought within close proximity can become useful for visualizing the dynamic actions of RNA assemblies and their interactions in real time with low background noise and eliminated necessity for covalently attached dyes. Here, we design and test several sets of F30 Broccoli aptamer splits, that we call fluorets, to compare their relative fluorescence and physicochemical stabilities. We show that the splits can be simply assembled either through one-pot thermal annealing or co-transcriptionally, thus allowing for direct tracking of transcription reactions via the fluorescent response. We suggest a set of rules that enable for the construction of responsive biomaterials that readily change their fluorescent behavior when various stimuli such as the presence of divalent ions, exposure to various nucleases, or changes in temperature are applied. We also show that the strand displacement approach can be used to program the controllable fluorescent responses in isothermal conditions. Overall, this work lays a foundation for the future development of dynamic systems for molecular computing which can be used to monitor real-time processes in cells and construct biocompatible logic gates.

A novel real-time analyzer for moving objects on freeway

2002 ◽  
Author(s):  
Jyh Chen ◽  
Jin-Tu Huang ◽  
Hsing-Chin Yeh ◽  
Chean-Mean Chen ◽  
Yen-Tseng Hsu
Keyword(s):  
Real Time ◽  
Moving Objects ◽  
Time Analyzer
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