Upscaling and Development of Linear Array Focused Laser Differential Interferometry for Simultaneous 1D Velocimetry and Spectral Profiling in High-Speed Flows

In this research a new configuration of linear array-focused laser differential interferometry (LA-FLDI) is described. This measurement expands on previous implementations of LA-FLDI through the use of an additional Wollaston prism. This additional prism expands the typical single LA-FLDI column into two columns of FLDI point pairs. The additional column of probed locations allows for increased spatial sampling of frequency spectra as well as the addition of simultaneous wall normal velocimetry measurements. The new configuration is used to measure the velocity profile and frequency content across a Mach 2 turbulent boundary layer at six wall normal locations simultaneously. Features of the measured spectra are shown to agree with expectations and the obtained boundary layer velocity profile is compared with previously obtained PIV measurements. The increase in simultaneously probed points provided by LA-FLDI is ideal for impulse facilities where spatial scanning via measurement system translation is not possible for a single run and techniques such as PIV may not be feasible. Initial testing was also carried out to determine if FLDI-based velocimetry can provide reasonable velocity profiles for adverse pressure gradients and over distributed roughness. Finally, a prototype photodiode array is proposed to simplify the optical setup for LA-FLDI and initial test results are provided comparing the impulse response of the prototype array to that of the amplified photodetectors currently in use

Integrated and adaptive traffic signal control for diamond interchange : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Mechatronics Engineering at Massey University, Albany, New Zealand

New dynamic signal control methods such as fuzzy logic and artificial intelligence developed recently mainly focused on isolated intersection. Adaptive signal control based on fuzzy logic control (FLC) determines the duration and sequence that traffic signal should stay in a certain state, before switching to the next state (Trabia et al. 1999, Pham 2013). The amount of arriving and waiting vehicles are quantized into fuzzy variables and fuzzy rules are used to determine if the duration of the current state should be extended. The fuzzy logic controller showed to be more flexible than fixed controllers and vehicle actuated controllers, allowing traffic to flow more smoothly. The FLC does not possess the ability to handle various uncertainties especially in real world traffic control. Therefore it is not best suited for stochastic nature problems such as traffic signal timing optimization. However, probabilistic logic is the best choice to handle the uncertainties containing both stochastic and fuzzy features (Pappis and Mamdani 1977) Probabilistic fuzzy logic control is developed for the signalised control of a diamond interchange, where the signal phasing, green time extension and ramp metering are decided in response to real time traffic conditions, which aim at improving traffic flows on surface streets and highways. The probabilistic fuzzy logic for diamond interchange (PFLDI) comprises three modules: probabilistic fuzzy phase timing (PFPT) that controls the green time extension process of the current running phase, phase selection (PSL) which decides the next phase based on the pre-setup phase logic by the local transport authority and, probabilistic fuzzy ramp-metering (PFRM) that determines on-ramp metering rate based on traffic conditions of the arterial streets and highways. We used Advanced Interactive Microscopic Simulator for Urban and Non-Urban Network (AIMSUN) software for diamond interchange modeling and performance measure of effectiveness for the PFLDI algorithm. PFLDI was compared with actuated diamond interchange (ADI) control based on ALINEA algorithm and conventional fuzzy logic diamond interchange algorithm (FLDI). Simulation results show that the PFLDI surpasses the traffic actuated and conventional fuzzy models with lower System Total Travel Time, Average Delay and improvements in Downstream Average Speed and Downstream Average Delay. On the other hand, little attention has been given in recent years to the delays experienced by cyclists in urban transport networks. When planning changes to traffic signals or making other network changes, the value of time for cycling trips is rarely considered. The traditional approach to road management has been to only focus on improving the carrying capacity relating to vehicles, with an emphasis on maximising the speed and volume of motorised traffic moving around the network. The problem of cyclist delay has been compounded by the fact that the travel time for cyclists have been lower than those for vehicles, which affects benefit–cost ratios and effectively provides a disincentive to invest in cycling issues compared with other modes. The issue has also been influenced by the way in which traffic signals have been set up and operated. Because the primary stresses on an intersection tend to occur during vehicle (commuter) peaks in the morning and afternoon, intersections tend to be set up and coordinated to allow maximum flow during these peaks. The result is that during off-peak periods there is often spare capacity that is underutilised. Phasing and timings set up for peaks may not provide the optimum benefits during off-peak times. This is particularly important to cyclists during lunch-time peaks, when vehicle volumes are low and cyclist volumes are high. Cyclists can end up waiting long periods of time as a result of poor signal phasing, rather than due to the demands of other road users being placed on the network. The outcome of this study will not only reduce the traffic congestion during peak hours but also improve the cyclists’ safety at a typical diamond interchange

CP asymmetries in the supersymmetric trilepton signal at the LHC

In the CP-violating Minimal Supersymmetric Standard Model, we study the production of a neutralino-chargino pair at the LHC. For their decays into three leptons, we analyze CP asymmetries which are sensitive to the CP phases of the neutralino and chargino sector. We present analytical formulas for the entire production and decay process, and identify the CP-violating contributions in the spin correlation terms. This allows us to define the optimal CP asymmetries. We present a detailed numerical analysis of the cross sections, branching ratios, and the CP observables. For light neutralinos, charginos, and squarks, the asymmetries can reach several 10%. We estimate the discovery potential for the LHC to observe CP violation in the trilepton channel.Comment: 39 pages, 8 figures, version to appear in EPJC, discussion(s) added, typo in (D.79), (D.118) corrected, new Fig. 7; The European Physical Journal C, Volume 72, Issue 3, 201

Analysis of focused laser differential interferometry

A computational method for predicting the output of a focused laser differential interferometer (FLDI) given an arbitrary density field is presented. The method is verified against analytical predictions and experimental data. The FLDI simulation software is applied to the problem of measuring Mack-mode wave packets in a hypervelocity boundary layer on a 5° half-angle cone. The software is shown to complement experiments by providing the necessary information to allow quantitative density fluctuation magnitudes to be extracted from experimental measurements

Optical Measurements of Viscous Interactions on a Hollow-Cylinder / Flare in a Mach 4 Freestream

Despite decades of research, shock-wave/boundary-layer interactions and laminar-turbulent transition remain uncertainties in the design of hypersonic vehicles. Due to the significant demand for hypersonic capabilities and the relevance of these flow physics to air-breathing, high-lift, hypersonic vehicles, continued study is necessary. In order to support such study at the University of Tennessee Space Institute, two optical diagnostics were investigated for use in the Mach 4 Ludwig tube at the Tennessee Aerothermal Laboratory, focused laser differential interferometry and schlieren. Significant attention was given to the theory behind and application of focused laser differential interferometry to support future work at the University of Tennessee Space Institute. These diagnostics were constructed and utilized in two studies, one investigating a laminar shock-wave/boundary-layer interaction on an axisymmetric hollow cylinder flare geometry, and one tracking the boundary layer transition along a hollow cylinder. Results of these studies show that FLDI and schlieren are an effective method for the non-intrusive study of boundary layer structure and breakdown, and show promising use for the study of shock-wave/boundary-layer interactions. Reported results include spectral distributions from the boundary layer, separation region, and reattachment region of a laminar shock-wave/boundary-layer interaction and from laminar, transitional, and fully turbulent regions in a boundary layer. In this study, the boundary layer was found to transition at a local Reynolds number of Re = 1.71 × 10^5 and gave way to fully turbulent behavior at Re = 3.34 × 10^5