SIMULATING FLOOD RECOVERY MANOEUVRES USING A FREE-RUNNING SUBMARINE MODEL

2021 ◽  
Vol 162 (A3) ◽  
Author(s):  
P Marchant ◽  
P Crossland
Keyword(s):  
Full Scale ◽  
Research Model ◽  
Control Performance ◽  
Model Scale ◽  
Average Accuracy ◽  
Free Running ◽  
Ballast Tanks ◽  
And Control ◽  
The Mathematical Model ◽  
Generate Model

Managing submarine safety, effectively, requires an understanding of many areas of platform performance, including its ability to manoeuvre. QinetiQ’s free-running submarine model (FRM) capability, the second generation Submarine Research Model (SRMII), forms a key part of the UK’s predictive manoeuvring capability that supports the MoD’s ability to conduct hydrodynamic assessment of the manoeuvring and control performance of the Royal Navy’s current and future submarines. Uniquely for an FRM, the SRMII has a large and capable ballast system. This is able to emulate a flooding incident within a submarine compartment and the subsequent emergency recovery procedures, which may include blowing the submarine’s main ballast tanks. This paper discusses how the SRMII’s ballast system was used to generate model-scale trajectories, which are not obtainable with many other FRMs. The experimental data were used to successfully validate the mathematical model, which predicts the maximum pitch angle response of a full-scale submarine to a compartment flood, to within an average accuracy of 1% at model-scale. However, the range of the non- dimensional flow angles the FRM exhibited was shown to be within that for a full-scale flood trajectory. Therefore, further tests have been proposed to increase the extent of the data in the future.

Simulating Flood Recovery Manoeuvres Using a Free-Running Submarine Model

2020 ◽  
Vol 162 (A3) ◽  
Author(s):  
P Marchant ◽  
P Crossland
Keyword(s):  
Full Scale ◽  
Research Model ◽  
Control Performance ◽  
Model Scale ◽  
Average Accuracy ◽  
Free Running ◽  
Ballast Tanks ◽  
And Control ◽  
The Mathematical Model ◽  
Generate Model

Managing submarine safety, effectively, requires an understanding of many areas of platform performance, including its ability to manoeuvre. QinetiQ’s free-running submarine model (FRM) capability, the second generation Submarine Research Model (SRMII), forms a key part of the UK’s predictive manoeuvring capability that supports the MoD’s ability to conduct hydrodynamic assessment of the manoeuvring and control performance of the Royal Navy’s current and future submarines. Uniquely for an FRM, the SRMII has a large and capable ballast system. This is able to emulate a flooding incident within a submarine compartment and the subsequent emergency recovery procedures, which may include blowing the submarine’s main ballast tanks. This paper discusses how the SRMII’s ballast system was used to generate model-scale trajectories, which are not obtainable with many other FRMs. The experimental data were used to successfully validate the mathematical model, which predicts the maximum pitch angle response of a full-scale submarine to a compartment flood, to within an average accuracy of 1% at model-scale. However, the range of the non-dimensional flow angles the FRM exhibited was shown to be within that for a full-scale flood trajectory. Therefore, further tests have been proposed to increase the extent of the data in the future.

scholarly journals Numerical Simulation of the Ship Resistance of KCS in Different Water Depths for Model-Scale and Full-Scale

2020 ◽  
Vol 8 (10) ◽  
pp. 745 ◽  
Author(s):  
Dakui Feng ◽  
Bin Ye ◽  
Zhiguo Zhang ◽  
Xianzhou Wang
Keyword(s):  
Water Depth ◽  
Full Scale ◽  
Scaled Model ◽  
Hull Form ◽  
Ship Resistance ◽  
Model Scale ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
The Mathematical Model ◽  
Water Depths

Estimating ship resistance accurately in different water depths is crucial to design a resistance-optimized hull form and to estimate the minimum required power. This paper presents a validation of a new procedure used for resistance correction of different water depths proposed by Raven, and it presents the numerical simulations of a Kriso container ship (KCS) for different water depth/draught ratios. Model-scale and full-scale ship resistances were predicted using in-house computational fluid dynamics (CFD) code: HUST-Ship. Firstly, the mathematical model is established and the numerical uncertainties are analyzed to ensure the reliability of the subsequent calculations. Secondly, resistances of different water depth/draught ratios are calculated for a KCS scaled model and a full-scale KCS. The simulation results show a similar trend for the change of model-scale and full-scale resistance in different water depths. Finally, the correction procedure proposed by Raven is briefly introduced, and the CFD resistance simulation results of different water depth/draught ratios are compared with the results estimated using the Raven method. Generally, the reliability of the HUST-Ship solver used for predicting ship resistance is proved, and the practicability of the Raven method is discussed.

ROKVISS - Space Robotics Dynamics and Control Performance Experiments at the ISS

2004 ◽  
Vol 37 (6) ◽  
pp. 333-338
Author(s):  
Bernd Schäfer ◽  
Bernhard Rebele ◽  
Klaus Landzettel
Keyword(s):  
Space Robotics ◽  
Control Performance ◽  
Dynamics And Control ◽  
And Control

The Failure of British Counter-Espionage against Germany, 1907–1914

1985 ◽  
Vol 28 (4) ◽  
pp. 835-862 ◽  
Author(s):  
Nicholas Hiley
Keyword(s):  
Full Scale ◽  
Joint Conference ◽  
Emergency Powers ◽  
And Control ◽  
Police Surveillance

Modern British counter-espionage effectively began in April 1907, when a joint conference of naval and military officials, formed the previous year to consider ‘the Powers Possessed by the Executive in Time of Emergency’, recommended both an immediate strengthening of the laws against espionage, and a War is Office investigation of ‘the question of police surveillance and control of aliens’. These recommendations were to prove an important initiative, and did much to determine the course of British counter-espionage before 1914, yet at the time they probably seemed little more than an airing of old grievances unlikely to find new support, for they were among the last remnants n. of the abortive ‘Emergency Powers Bill’ which the War Office intelligence department had been advocating to strengthen home defence ever since the invasion scare of 1888. The 1906 joint conference had in fact hoped to further the cause of this great legislative package, with its radically new powers of access, requisition and seizure but, faced with the Liberal administration's commitment to the ‘continuous principle’ that a full-scale landing was impossible, had been forced instead to confine itself to the purely naval and military aspects of home defence. As its report confessed in April 1907, in the prevailing climate of opinion the only hope for the great ‘Emergency Powers Bill’ was as a series of ‘small and independent measures’.

Application of PID in Controllable Pitch Propeller of a Multipurpose Ocean Tug

2013 ◽  
Vol 464 ◽  
pp. 253-257
Author(s):  
Hui Fang Chen
Keyword(s):  
Control System ◽  
Automatic Control ◽  
Automatic Control System ◽  
High Reliability ◽  
Control Process ◽  
Good Control ◽  
Control Performance ◽  
Hardware Configuration ◽  
Design Idea ◽  
And Control

This paper takes the automatic control system of controllable pitch propeller in a multipurpose ocean tug as an example to describe the application of the S7-200 series PLC in the control system of 4500 horse power controllable pitch propeller in detail. The principle of control system is addressed, as well as the hardware configuration, the design idea of the main software and control process. The system shows high reliability, accuracy and good control performance in practical in practical running.

Controller Parameters Optimization of PWM Converter Based DFIG

2014 ◽  
Vol 672-674 ◽  
pp. 1012-1015
Author(s):  
He Zhu ◽  
Da Tian Xu ◽  
Hao Ran Zhao
Keyword(s):  
Control Strategy ◽  
Simplex Algorithm ◽  
Parameters Optimization ◽  
Pwm Converter ◽  
Stator Flux ◽  
Grid Side ◽  
Rotor Side Converter ◽  
Grid Side Converter ◽  
And Control ◽  
The Mathematical Model

Based on the mathematical model of the PWM converter, control strategy of the grid-side converter directed by the grid voltage and control strategy of the rotor-side converter directed by the stator flux were established combining the vector control theory. The method using the nonlinear simplex algorithm to optimize the PI control parameters of the DFIG unit was first proposed, optimization results proved that this method had good practicality and robustness.

Development of a Ring Permeability Test System

2010 ◽  
Vol 136 ◽  
pp. 153-157
Author(s):  
Yu Hong Du ◽  
Xiu Ming Jiang ◽  
Xiu Ren Li
Keyword(s):  
Control System ◽  
Control Method ◽  
Dynamic Performance ◽  
Experimental Tests ◽  
Measuring Method ◽  
Test System ◽  
Fluid Theory ◽  
And Control ◽  
Relationship Of ◽  
The Mathematical Model

To solve the problem of detecting the permeability of the textile machinery, a dedicated test system has been developed based on the pressure difference measuring method. The established system has a number of advantages including simple, fast and accurate. The mathematical model of influencing factors for permeability is derived based on fluid theory, and the relationship of these parameters is achieved. Further investigations are directed towards the inherent characteristics of the control system. Based on the established model and measuring features, an information fusion based clustering control system is proposed to implement the measurement. Using this mechanical structure, a PID control system and a cluster control system have been developed. Simulation and experimental tests are carried out to examine the performance of the established system. It is noted that the clustering method has a high dynamic performance and control accuracy. This cluster fusion control method has been successfully utilized in powder metallurgy collar permeability testing.

A prey–predator model and control of a nematodes pest using control in banana: Mathematical modeling and qualitative analysis

2021 ◽  
pp. 2150089
Author(s):  
Sudhakar Yadav ◽  
Vivek Kumar
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Local Stability ◽  
Detection Method ◽  
Initial Release ◽  
Pest Detection ◽  
Predator Model ◽  
And Control ◽  
The Mathematical Model ◽  
Theoretical Results

This study develops a mathematical model for describing the dynamics of the banana-nematodes and its pest detection method to help banana farmers. Two criteria: the mathematical model and the type of nematodes pest control system are discussed. The sensitivity analysis, local stability, global stability, and the dynamic behavior of the mathematical model are performed. Further, we also develop and discuss the optimal control mathematical model. This mathematical model represents various modes of management, including the initial release of infected predators as well as the destroying of nematodes. The theoretical results are shown and verified by numerical simulations.

A New Method of Modeling Underexpanded Exhaust Plumes for Wind Tunnel Aerodynamic Testing

1989 ◽  
Vol 111 (4) ◽  
pp. 748-754
Author(s):  
V. Salemann ◽  
J. M. Williams
Keyword(s):  
Wind Tunnel ◽  
Free Stream ◽  
Dynamic Pressure ◽  
Pressure Ratio ◽  
Area Ratio ◽  
Full Scale ◽  
New Method ◽  
Thrust Coefficient ◽  
Model Scale ◽  
Exhaust Plumes

A new method for modeling hot underexpanded exhaust plumes with cold model scale plumes in aerodynamic wind tunnel testing has been developed. The method is applicable to aeropropulsion testing where significant interaction between the exhaust and the free stream and aftbody may be present. The technique scales the model and nozzle external geometry, including the nozzle exit area, matches the model jet to free-stream dynamic pressure ratio to full-scale jet to free-stream dynamic pressure ratio, and matches the model thrust coefficient to full-scale thrust coefficient. The technique does not require scaling of the internal nozzle geometry. A generalized method of characteristic computer code was used to predict the plume shapes of a hot (γ = 1.2) half-scale nozzle of area ratio 3.2 and of a cold (γ = 1.4) model scale nozzle of area ratio 1.3, whose pressure ratio and area ratio were selected to satisfy the above criteria and other testing requirements. The plume shapes showed good agreement. Code validity was checked by comparing code results for cold air exhausting into a quiescent atmosphere to pilot surveys and shadowgraphs of model nozzle plumes taken in a static facility.

Development of a Scaled Rotor Blade for Tank Tests of Floating Wind Turbine Systems

2018 ◽  
Author(s):  
Paul Schünemann ◽  
Timo Zwisele ◽  
Frank Adam ◽  
Uwe Ritschel
Keyword(s):  
Wind Turbine ◽  
Rotor Blade ◽  
Turbine Rotor ◽  
Full Scale ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Model Scale ◽  
Floating Wind Turbine ◽  
Hydrodynamic Effects ◽  
Wind Turbine Rotor

Floating wind turbine systems will play an important role for a sustainable energy supply in the future. The dynamic behavior of such systems is governed by strong couplings of aerodynamic, structural mechanic and hydrodynamic effects. To examine these effects scaled tank tests are an inevitable part of the design process of floating wind turbine systems. Normally Froude scaling is used in tank tests. However, using Froude scaling also for the wind turbine rotor will lead to wrong aerodynamic loads compared to the full-scale turbine. Therefore the paper provides a detailed description of designing a modified scaled rotor blade mitigating this problem. Thereby a focus is set on preserving the tip speed ratio of the full scale turbine, keeping the thrust force behavior of the full scale rotor also in model scale and additionally maintaining the power coefficient between full scale and model scale. This is achieved by completely redesigning the original blade using a different airfoil. All steps of this redesign process are explained using the example of the generic DOWEC 6MW wind turbine. Calculations of aerodynamic coefficients are done with the software tools XFoil and AirfoilPrep and the resulting thrust and power coefficients are obtained by running several simulations with the software AeroDyn.

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