Underwater pipelines are the channels for oil transportation in sea. In course of pipeline operation, leakage accidents occur from time to natural and man-made reasons which result economic losses environmental pollution. To avoid pollution, damage detection underwater must be carried out. this paper, based on histogram oriented gradient (HOG) support vector machine (SVM), a non-contact ultrasonic imaging method is proposed detect shedding metal external anti-corrosion layer. Firstly,...

To better study the sea-keeping response behavior of unmanned surface vehicles (USVs) in coastal intersecting waves, a prediction is conducted using CFD method this paper, which USV with shape small-scale catamaran and designed target for high-speed navigating considered. The proved to be good enough at ship can utilized abundant forms towing experiment simulations, including planar motion mechanism experiments. regular irregular wave generation numerical also virtualize actual tank work,...

The autonomous driving is rapid developing recently and model predictive controls (MPCs) have been widely used in unmanned vehicle trajectory tracking. MPCs are advantageous because of their modeling, rolling optimization, feedback correction. In recent years, most studies on tracking only linear to solve MPC algorithm shortcomings real time. Previous not investigated problems under conditions where speeds too fast or curvatures change rapidly, the poor accuracy approximate linearization. A...

The safety of unmanned ship berthing is paramount importance. In order to explore the influence wind and wave coupling, a computational fluid dynamics (CFD) model was established, characteristics speed field, pressure vortex have been obtained under different speed, direction, quay wall distances. results show that total resistance hull against current can be about 1.60 times higher compared downstream resistance, water flow dominant factor, accounting for more than 80% resistance. When...

An overall framework of the virtual testing system has been established based on analysis requirements for autonomous navigation performance unmanned surface vehicles (USVs). This consists several modules, including environment module, motion sensor and 3D visualization module. Firstly, within robot operating (ROS) environment, a three-dimensional was generated by combining actual wave spectra with Gerstner waves. By designing power plugin USV navigation, made to reflects coupled model USVs...

In response to the urgent need for quantitative evaluation of obstacle avoidance performance an unmanned ship, a model is established evaluate quantitatively perception performance, static and dynamic ship. The base data calculating are derived from shore-based database; factor layer evaluated by cost function method. Based on model, score ship obtained analysis 50 100 m buoy island test. testing single obstacle, continuous inflection 68.8 points. For buoys as obstacles, 64.13 points in...

This work develops a heat transfer model of thermoelectric generator to explore the coupled relationship between high temperature exhaust flows, structure, and external cooling air. The results showed that fins reached uniform temperature, for rated speed, average is 474 K. design scheme tested by installing it in 4-cylinder turbocharged Diesel engine system. Comparison test simulation as speed in-creased, inlet outlet temperatures exhibited parabolic trend increase. water top, middle,...

Aiming at the problems existing in teaching of fluid mechanics theory, this paper puts forward goal introducing CFD (Computational Fluid Dynamics) software teaching, Combining with goal, discusses bridging strategy between theory and Engineering application: (1) Motivate students using visual display flow phenomenon close to life or engineering practice; (2) Deepen understanding concepts principles based on solution process; (3) basic equations their applications through combination "digital...

To solve the problem of uneven dust cleaning in filter cartridges, a simple and easy-to-install “branch-type” nozzle structure was designed to improve efficiency. In this study, numerical simulations, range analysis methods, orthogonal experimental design, back-blowing experiments, powder experiments were conducted. By choosing uniformity as evaluation index for performance, with flow distribution coefficient A, length branch pipe B, outlet diameter main C factors, ignoring interaction...

Damage to the body or critical components caused by stone strikes automotive coatings affects safety of car. More and more attention are being paid study anti-stone-damage mechanism coatings. Firstly, a computational fluid dynamics (CFD) model was established based on single-impact anti-stone tester, simulation results show following: (a) At 90° incidence, air pressure impact suddenly rapidly increases when semicircular surface projectile velocity is greater than 30 m/s. The conical at...

In order to avoid the influence of test system itself on autonomous navigation and performance accuracy unmanned surface vehicles (USVs), a method for obstacle-avoidance USVs based mobile-buoy–shore multisource-sensing-data fusion is proposed. this method, mobile-buoy-integrated designed (that is, instrument installed mobile buoy). The buoy both carrier obstacle. software hardware functions are realized in modules, monitoring function USV by trajectory-tracking perception preprocessing shore...

Firstly, a performance test system was established for exhaust muffler based on the existing engine bench and physical layout of vehicle system. Secondly, experimental data original back-pressure, noise tailpipe were recorded, pressure loss insertion computed. An optimized design scheme proposed verification experiment conducted according to previous results requirements. Finally, show that back-pressure is reduced at all speeds, especially high speed (4800rpm or above) by about 4kPa;...

Unsteady simulation of heat transfers for vehicle exhaust system plays an important role in development process. Based on STAR-CD software, a sedan model, which includes the gas, pipes and aftertreatment devices, was established. In this complicated boundary conditions between fluid solid, need to be specified non-coupled models, are now part solution do not specified. A three-dimensional unsteady undertaken transfer characteristics system. The with periodic pulsating temperature were...