\n High-speed railway aerodynamics is the key basic science for solving the bottleneck problem of high-speed railway development. This paper systematically summarizes the aerodynamic research relating to China’s high-speed railway network. Seven key research advances are comprehensively discussed, including train aerodynamic drag-reduction technology, train aerodynamic noise-reduction technology, train ventilation technology, train crossing aerodynamics, train/tunnel aerodynamics, train/climate environment aerodynamics, and train/human body aerodynamics. Seven types of railway aerodynamic test platform built by Central South University are introduced. Five major systems for a high-speed railway network—the aerodynamics theoretical system, the aerodynamic shape (train, tunnel, and so on) design system, the aerodynamics evaluation system, the 3D protection system for operational safety of the high-speed railway network, and the high-speed railway aerodynamic test/computation/analysis platform system—are also introduced. Finally, eight future development directions for the field of railway aerodynamics are proposed. For over 30 years, railway aerodynamics has been an important supporting element in the development of China’s high-speed railway network, which has also promoted the development of high-speed railway aerodynamics throughout the world.

Review of research on high-speed railway aerodynamics in China

With developments of micro-machining and advanced functional materials, smart actuators have been developed and applied in various micro underwater vehicles (MUVs) or micro underwater robots. Since there is a tradeoff between the miniature size and output performance for MUVs driven by traditional electromagnetic motors, piezoelectric motors with features of compact structure, large force or torque at small size and no electromagnetic interference provide another promising alternative for actuating MUVs. However, there is a few research to explore the possibility of utilizing piezoelectric motors to realize underwater actuations. In this paper, a novel piezoelectric inertial rotary motor is designed to power the underwater vehicle, which is capable of forward swimming, rotating, rising and diving. This motor consists of two rotors and one disk type stator. One piece of piezoelectric wafer adhered to the bottom face of the stator’s metal disk is used to excite the radial in-plane vibration mode of stator’s outer ring, which is converted into the revolved motion of the inner tube through the connection beams. To utilize the inertial driving mechanism, the motor works at a “slip-slip” mode by the saw-tooth type driving signal. One prototype motor with the appearance size of Φ 20 mm × 20 mm and weight of 3.6 g is designed, fabricated and characterized. Experimental results show that the prototype motor could rotate at a steady speed of 2200 r/min with 150 Vp-p driving voltage. In addition, the motor also performs well with a slightly decrease of operating speed in underwater environments when the silver electrode is coated by waterproof material. Consequently, sealing ring is not necessary for the proposed motor as immersed in water, which is different with conventional electromagnetic motors and enables the actuation unit to be smaller. And then, the prototype motor is coupled with a propeller to build a thruster, which could output the steady speed and maximum propulsion force of 1200 r/min and 4.6 mN, respectively. Finally, the thruster is installed in a spherical swimming robot, and the velocity of the robot could reach 80 mm/s. With merits of simple structure, compact size and great waterproof feasibility, the proposed piezoelectric inertial motor opens a new avenue for developing advanced and flexible MUVs.

A novel piezoelectric inertial rotary motor for actuating micro underwater vehicles

Ship stability, dynamics and safety : Status and perspectives from a review of recent STAB conferences and ISSW events

In Naval Architecture, the concept of "stability" has a very wide meaning, embracing ship stability fundamentals with ship dynamics and ultimately ship safety. As such, the subject is of paramount ...

Ship Stability, Dynamics and Safety: Status and Perspectives

Cardiac mechanical models analysis of arterial hemodynamics using the principle of wave separation microvascular networks extracorporeal systems artificial vessel and grafts biomechanical aspects of intercoronary stents cardiac assist devices mechanical circulatory assist devices.

Fluid structure interaction

Liquefied Natural Gas (LNG) tanker often travels through shallow waters with visible banks to load and unload its hazardous cargo. Manoeuvring of vessel in shallow water is relatively difficult and always exposed to higher risk of grounding and collision compared to deep water due to effect of ship-bank interaction. This research work examines ship-bank interaction effects of a LNG tanker in shallow water. CFD analysis is performed to investigate the hull hydrodynamic forces/moments and ship-bank interaction forces/moments which are further validate by captive model tests.

Assessment of ship-bank interactions On LNG tanker in shallow water

A Multi Input Multi Output (MIMO) fuzzy estimator variable structure control (VSC) which containing an on-line controller coefficient tuned with the aim of a fuzzy back stepping algorithm. Satisfactory trajectories tracking among the internal combustion engine (IC engine) air to fuel ratio and the preferred input is certified in this paper. The fuzzy controller deployed in developed fuzzy estimator variable structure controller works using Lyapunov fuzzy inference system (FIS) with least model based rule base. Function among variable structure function, error and the error’s rate is represented by model. The outputs show fuel ratio. The fuzzy back stepping tactic is an on-line variable structure function fixing with the aim of an adaptive approach. MIMO fuzzy estimator and VSC performance with an on-line fuzzy back stepping algorithm (FBAFVSC) tuned with the aim of controller coefficient is confirmed using a comparison with VSC and planned approach. Simulation outputs indicate excellent presentation of fuel ratio in attendance of ambiguity and exterior annoyance.

Designing Fuzzy Backstepping Adaptive Based Fuzzy Estimator Variable Structure Control: Applied to Internal Combustion Engine

Wing configuration is a parameter that affects the performance of wing-in-ground effect (WIG) craft. In this study, the aerodynamic characteristics of a new compound wing were investigated during ground effect. The compound wing was divided into three parts with a rectangular wing in the middle and two reverse taper wings with anhedral angle at the sides. The sectional profile of the wing model is NACA6409. The experiments on the compound wing and the rectangular wing were carried to examine different ground clearances, angles of attack, and Reynolds numbers. The aerodynamic coefficients of the compound wing were compared with those of the rectangular wing, which had an acceptable increase in its lift coefficient at small ground clearances, and its drag coefficient decreased compared to rectangular wing at a wide range of ground clearances, angles of attack, and Reynolds numbers. Furthermore, the lift to drag ratio of the compound wing improved considerably at small ground clearances. However, this improvement decreased at higher ground clearance. The drag polar of the compound wing showed the increment of lift coefficient versus drag coefficient was higher especially at small ground clearances. The Reynolds number had a gradual effect on lift and drag coefficients and also lift to drag of both wings. Generally, the nose down pitching moment of the compound wing was found smaller, but it was greater at high angle of attack and Reynolds number for all ground clearance. The center of pressure was closer to the leading edge of the wing in contrast to the rectangular wing. However, the center of pressure of the compound wing was later to the leading edge at high ground clearance, angle of attack, and Reynolds number.

Experimental Aerodynamic Characteristics of a Compound Wing in Ground Effect

The configuration and service condition of a wing can influence the performance of wing-in-ground effect (WIG) craft. In this study, the aerodynamic performance of compound wings in ground effect was numerically investigated through a parametric design study. The compound wing is divided into three parts with one rectangular wing in the middle and two reverse taper wings with an anhedral angle at the sides. A NACA6409 airfoil was employed as a section of the wing. The design parameters included the span size, anhedral angle, and taper ratio plus two boundary conditions: ground clearance and Reynolds number. The three-dimensional, Reynolds-averaged Navier-Stokes (RANS) equations were solved numerically. A realizable k−e turbulent model was used to compute the effects of the turbulent flow over the wing surface. The computational results of the basic wing were compared with the experimental data of other published works. Next, the aerodynamic performance of the compound wings was computed for variou...

Design Parametric Study of a Compound Wing-in-Ground Effect. I: Aerodynamics Performance

Fuzzy logic (FL) systems are widely established as a technology offering an alternative system to tackle compound and ill defined problems. They can be trained from examples, are fault tolerant in the sense that they are capable to grip noisy and deficient data, are able to deal with non-linear problems, and once trained can perform prediction and generalization at high speed. in this paper a simple fuzzy logic control has been developed which is used for defining engine system faults and control and maintain them in a normal range  without use any complicated mathematical equation and any fault sensor.

Agoes Priyanto

Papers

Assessment of ship-bank interactions On LNG tanker in shallow water

Designing Fuzzy Backstepping Adaptive Based Fuzzy Estimator Variable Structure Control: Applied to Internal Combustion Engine

Experimental Aerodynamic Characteristics of a Compound Wing in Ground Effect

Design Parametric Study of a Compound Wing-in-Ground Effect. I: Aerodynamics Performance

A simple fuzzy logic diagnosis system for control of internal combustion engines