Boundary layer scaling in Rayleigh-Benard convection

Accepted versio

Some aspects of laboratory testing and computer modelling of two-stage compressors with inter and after-cooling

Laboratory testing and computer simulation of a two-stage reciprocating air compressor with inter and after-cooling was undertaken with the purpose of studying the physical processes occurring in the compressor and obtaining information useful for design purposes. The testing includes measurements of instantaneous temperature and pressure in suction and delivery chambers and interconnecting pipes in both cylinders, instantaneous torque and average quantities, during the steady and transient state operation. Results are presented and the problems are discussed. The suitability of the micro-thennocouple for measurement of instantaneous temperatures, its dynamic behaviour and strength limitations, as well as mounting and calibration problems are considered. The measurement of pulsating pressure by means of piezoelectric and capacitive transducers in combined use are presented with specific reference to the effect of transducer location. Results are reported of the computer modelling of the thermodynamic processes including the unsteady gas flow in the piping system with friction and heat transfer effects, and comparison made with experimental data. Some practical implications are discussed of the testing and computer modelling upon desig

Some aspects of laboratory testing and computer modelling of two-stage compressors with inter and after-cooling

Laboratory testing and computer simulation of a two-stage reciprocating air compressor with inter and after-cooling was undertaken with the purpose of studying the physical processes occurring in the compressor and obtaining information useful for design purposes. The testing includes measurements of instantaneous temperature and pressure in suction and delivery chambers and interconnecting pipes in both cylinders, instantaneous torque and average quantities, during the steady and transient state operation. Results are presented and the problems are discussed. The suitability of the micro-thennocouple for measurement of instantaneous temperatures, its dynamic behaviour and strength limitations, as well as mounting and calibration problems are considered. The measurement of pulsating pressure by means of piezoelectric and capacitive transducers in combined use are presented with specific reference to the effect of transducer location. Results are reported of the computer modelling of the thermodynamic processes including the unsteady gas flow in the piping system with friction and heat transfer effects, and comparison made with experimental data. Some practical implications are discussed of the testing and computer modelling upon desig

Vehicle Sensing and Communications using LED Headlights to Enhance the Performance of Intelligent Transportation Systems: Proof of Concept, Implementation, and Applications

This project investigates the use of vehicle light-emitting diode (LED) headlamp devices for improving the accuracy and reliability of traffic (sensing and communication) data measurements required for developing effective intelligent transportation systems (ITS) technologies and solutions. Vehicular communication and sensing technologies are mainly based on conventional radio frequency (RF) or laser technologies. These systems suffer from several issues such as RF interference and poor performance in scenarios where the incidence angle between the speed detector and the vehicle is rapidly varying. Introducing a new sensing technology will add diversity to these systems and enhance the reliability of the real-time data. In this project, we proposed and investigated a novel speed estimation sensing system named “Visible Light Detection and Ranging (ViLDAR)” (patent pending). ViLDAR utilizes visible light-sensing technology to measure the variation of the vehicle’s headlamp light intensity to estimate the vehicle speed. Similarly, visible light sensing technology is used for data communication purposes, where the vehicle headlamp is utilized for wireless data transmission purposes. This project outlines the ViLDAR system simulations, implementation including hardware and software components, experimental evaluation in both laboratory and outdoor environments. The experimental measurement settings of the ViLDAR experiments are detailed. Encouraging results for both sensing and communication scenarios are obtained. The outcome of this proof-of-concept study both in the laboratory and outdoor validates the merit of the proposed technology in speed estimation (sensing) and data communication. The outcomes of this project will inspire a wide and diverse range of researchers, scientists and practitioners from the ITS community to explore this new and exciting technology. This project built initial steps in exploring this new sensing and communication modality using vehicle headlamps, leaving open a wide field for exploration and novel research

Modelling of content-aware indicators for effective determination of shot boundaries in compressed MPEG videos

In this paper, a content-aware approach is proposed to design multiple test conditions for shot cut detection, which are organized into a multiple phase decision tree for abrupt cut detection and a finite state machine for dissolve detection. In comparison with existing approaches, our algorithm is characterized with two categories of content difference indicators and testing. While the first category indicates the content changes that are directly used for shot cut detection, the second category indicates the contexts under which the content change occurs. As a result, indications of frame differences are tested with context awareness to make the detection of shot cuts adaptive to both content and context changes. Evaluations announced by TRECVID 2007 indicate that our proposed algorithm achieved comparable performance to those using machine learning approaches, yet using a simpler feature set and straightforward design strategies. This has validated the effectiveness of modelling of content-aware indicators for decision making, which also provides a good alternative to conventional approaches in this topic

Improved Unsteady RANS Models Applied to Jet Transverse to a Pipe Flow

An unsteady RANS model is developed in order to simulate the complex situations involving both free and bounded flows. This model tuned to catch coherent flow structures is developed both in the k-ε and k-l approaches. The full 3D geometry of a round jet exiting from a reservoir into a pipe has been computed. Periodic conditions are applied in order to compare with an experiments consisting of eight jets exiting in a cross pipe flow. Improvement has been obtained with this URANS turbulence model compared to RANS and good agreement compared with experiments has been obtained. Unsteady phenomena are reproduced by the model and provide more insight into the physical properties of the flow and of the transport of a passive scalar