scholarly journals SIMULASI NUMERIK KENDALI KAPAL CEPAT TAK BERAWAK DUA PROPELLER TANPA RUDDER

2021 ◽  
Vol 20 (2) ◽  
pp. 107-113
Author(s):  
Muhammad Arifudin Lukmana ◽  
Qisthi Alhazmi Hidayatur-Rohman ◽  
Fahrudin Fahrudin ◽  
Noverdo Saputra
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Settling Time ◽  
Forward Motion ◽  
Fish Mapping ◽  
Automation Control

This paper discusses the simulation of automation control and hull manufacturing on a fast boat. This high-speed boat that will be carried out for fish mapping. This study uses a numerical simulation to predict its motion. The experiment was carried out 3 times in forward motion, and 3 times in turn motion. The ship’s time and movement in ideal conditions will be recorded for each experiment. With the PID value for forward overshoot with values such as: 8.94%, 30.86%, and 40.60%, while turning overshoot is obtained, among others: 25.77%, 49.82%, and 61.15% Then the advanced settling time obtained includes: 0.91 seconds, 3.84 seconds, and 5.31 seconds. The settling time for turns is: 1,022 seconds, 0.85 seconds, and 0.84 seconds These values are obtained from the simulation graph of the three-dof formulas for surge, sway, yaw.

Numerical simulation of high-speed civil transport inlet operability with angle of attack

AIAA Journal ◽  
1998 ◽  
Vol 36 ◽  
pp. 1223-1229
Author(s):  
Ge-Cheng Zha ◽  
Doyle Knight ◽  
Donald Smith ◽  
Martin Haas
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Angle Of Attack

Numerical Simulation of High-Speed Crack Propagating and Branching Phenomena

2016 ◽  
Vol 37 (7) ◽  
pp. 729-739
Author(s):  
GU Xin-bao ◽  
◽  
ZHOU Xiao-ping ◽  
XU Xiao ◽  
Keyword(s):  
Numerical Simulation ◽  
High Speed

scholarly journals Variable step control to improve scanning speed of gene sequencing stage

2021 ◽  
pp. 002029402110022
Author(s):  
Xiaohua Zhou ◽  
Jianbin Zheng ◽  
Xiaoming Wang ◽  
Wenda Niu ◽  
Tongjian Guo
Keyword(s):  
Motion Control ◽  
High Precision ◽  
High Speed ◽  
Stable State ◽  
Gene Sequencing ◽  
Scanning Speed ◽  
Settling Time ◽  
Step Motion ◽  
Variable Step ◽  
Step Control

High-speed scanning is a huge challenge to the motion control of step-scanning gene sequencing stage. The stage should achieve high-precision position stability with minimal settling time for each step. The existing step-scanning scheme usually bases on fixed-step motion control, which has limited means to reduce the time cost of approaching the desired position and keeping high-precision position stability. In this work, we focus on shortening the settling time of stepping motion and propose a novel variable step control method to increase the scanning speed of gene sequencing stage. Specifically, the variable step control stabilizes the stage at any position in a steady-state interval rather than the desired position on each step, so that reduces the settling time. The resulting step-length error is compensated in the next acceleration and deceleration process of stepping to avoid the accumulation of errors. We explicitly described the working process of the step-scanning gene sequencer and designed the PID control structure used in the variable step control for the gene sequencing stage. The simulation was performed to check the performance and stability of the variable step control. Under the conditions of the variable step control where the IMA6000 gene sequencer prototype was evaluated extensively. The experimental results show that the real gene sequencer can step 1.54 mm in 50 ms period, and maintain a high-precision stable state less than 30 nm standard deviation in the following 10 ms period. The proposed method performs well on the gene sequencing stage.

Numerical Simulation of Flowfield around High Speed Trains Passing by each other at the same Speed

2011 ◽  
Vol 97-98 ◽  
pp. 698-701
Author(s):  
Ming Lu Zhang ◽  
Yi Ren Yang ◽  
Li Lu ◽  
Chen Guang Fan
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Flow Field ◽  
Point Source ◽  
High Speed ◽  
Stokes Equations ◽  
Field Structure ◽  
Vehicle Speed ◽  
Mesh Method ◽  
High Speed Trains

Large eddy simulation (LES) was made to solve the flow around two simplified CRH2 high speed trains passing by each other at the same speed base on the finite volume method and dynamic layering mesh method and three dimensional incompressible Navier-Stokes equations. Wind tunnel experimental method of resting train with relative flowing air and dynamic mesh method of moving train were compared. The results of numerical simulation show that the flow field structure around train is completely different between wind tunnel experiment and factual running. Two opposite moving couple of point source and point sink constitute the whole flow field structure during the high speed trains passing by each other. All of streamlines originate from point source (nose) and finish with the closer point sink (tail). The flow field structure around train is similar with different vehicle speed.

AERODYNAMIC LIFT FORCES ON MULTIHULLED MARINE VEHICLES

2021 ◽  
Vol 152 (A2) ◽  
Author(s):  
A G W Williams ◽  
M Collu ◽  
M H Patel
Keyword(s):  
High Speed ◽  
Vehicle Stability ◽  
Aerodynamic Design ◽  
Forward Motion ◽  
Marine Vehicles ◽  
Marine Transport ◽  
Stability Model ◽  
Lift Forces ◽  
High Payload ◽  
Aerodynamic Lift

The need for high-speed high-payload craft has led to considerable efforts within the marine transport industry towards a vehicle capable of bridging the gap between conventional ships and aircraft. One such concept uses the forward motion of the craft to create aerodynamic lift forces on a wing-like superstructure and hence, reduce the displacement and skin friction. This paper addresses the specific aerodynamic design of multihull for optimal lift production and shows that significant efficiency can be achieved through careful shaping of a ducted hull, with lift-to-drag ratios of nearly 50 for a complete aerodynamic hull configuration. Further analysis is carried out using a hybrid vehicle stability model to determine the effect of such aerodynamic alleviation on a theoretical planing hull. It is found that the resistance can be halved for a fifty metre, three hundred tonne vehicle with aerodynamic alleviation travelling at 70 knots. Results are presented for a candidate vessel.

Stability Enhancement of Supercavitating Projectiles by Unsteady Air Injection

2005 ◽  
Author(s):  
Yasmin Khakpour ◽  
Miad Yazdani
Keyword(s):  
Numerical Simulation ◽  
Drag Reduction ◽  
High Speed ◽  
The Body ◽  
Air Injection ◽  
Cavity Surface ◽  
The Stability ◽  
Stability Enhancement

In this work, numerical simulation is used to study the stability enhancement of high speed supercavitating hydrofoils. Although supercavitation is known as one of the most effective methods for drag reduction, producing the cavity, either by ventilation or by cavitator at front of the body, may cause some instabilities on cavity surface and thus on the projectile’s motion. Therefore removing these instabilities comes as an important point of discussion. First of all, we calculate the sources of instabilities and measure respective forces and then present some approaches that significantly reduce these instabilities. One of these methods that could produce more stable supercavities is injecting of the air into the cavity unsteadily which varies through the projectile’s surface. This approach is provided by arrays of slots distributed on the projectile’s surface and unsteady injection is modeled over the surface. Furthermore, the position of ventilation, dramatically affects the stability like those in aerodynamics. In all approaches it is assumed that the supercavity covers the whole of the body, however the forces caused by the wakes, formed behind the body are taken into account. The calculation is performed at three cavitation numbers with respective velocities of 40 m/s, 50 m/s, 60 m/s.

Behavior of Bubble in Small Water Tank Used for Food Processing Using Underwater Shock Wave

2011 ◽  
Vol 673 ◽  
pp. 225-230 ◽  
Author(s):  
Hideki Hamashima ◽  
Manabu Shibuta ◽  
Shigeru Itoh
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Food Processing ◽  
High Speed ◽  
Underwater Explosion ◽  
Video Camera ◽  
Experimental Result ◽  
Water Tank ◽  
Underwater Shock Wave ◽  
Small Water

The food processing technology using a shock wave can prevent deterioration of the food by heat because it can process food in a short time. Generally, since the shock wave used for food processing is generated by underwater explosion, the load of a shock wave to the food becomes very complicated. Therefore, in order to process safely, it is important to clarify the behaviors of the shock wave and the bubble pulse generated by underwater explosion. In this research, in order to investigate the behavior of the shock wave in the water tank used for food processing, the optical observation experiment and the numerical simulation were performed. In the experiment, the shock wave generated by underwater explosion was observed with the high-speed video camera. The numerical simulation about the behavior of bubble pulse was performed using analysis software LS-DYNA. Comparing and examining were performed about the experimental result and the numerical simulation result. The result of the numerical simulation about the behavior of the shock wave generated by underwater explosion and the shock wave generated by the bubble pulse and the bubble pulse was well in agreement with the experimental result.

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