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The paper suggests a modification of AUSMPW+ scheme designed to low Mach number. For Mach number vanishing, AUSMPW+ scheme has an excessive numerical dissipation to result in the incorrect scaling of pressure and density fluctuations. The modification rescales all velocity components in the numerical flux by the local Mach number. The improved method reduces the dissipation and recovers the correct...
A new computational method of computational fluid dynamics (CFD) coupled with rigid body dynamics (RBD) and flight control system (FCS) is developed. In simulations of FCS, the robust and simpler fuzz control method is used instead of the usual PID method. Taking the control of pitching attitude as an example, virtual flight simulations of the basic finner projectile are presented. Simulation results...
In this work we explored the high-order Flux Reconstruction/correction procedure via reconstruction (FR/CPR) in inviscid low Mach number flow calculation. The method presented here is designed to improve the accuracy of the solution at low Mach numbers of the compressible Euler equations. The algorithm is based on modified low dissipation numerical Euler flux functions within FR framework, and the...
The study of high accuracy numerical schemes is a hot topic for decades in the field of compressible turbulence simulations. Linear compact schemes, high-order shock-capturing schemes and the hybrid schemes are three types of schemes used in today's turbulent flow simulations. The fifth-order compact scheme, WENO scheme and hybrid compact-WENO scheme are introduced as the representatives of these...
Turbulence and shock waves interactions occur in a wide range of applications, such as mixing, flow separation and combustion. However, it is still a challenge to accurately simulate these problems. The two demands seem contradictory: the simulation of small turbulence scales requires non-dissipative scheme while the capture of shock requires dissipative scheme. We evaluate the performance of several...
Thermal control has become a great challenge for 3D-ICs due to the ever increasing power density and 3D integration. Among techniques to address the problem, fast thermal simulation approach is basically required to accurately characterize the runtime temperature variations of 3D-ICs. In this paper, we propose an accurate and fast leakage-aware thermal simulation approach for 3D-ICs with consideration...
Visible Light Communication (VLC) has many advantages such as high-speed data transmission and non-frequency authorization, which provided a good solution for indoor access environment with an effective and energy-saving way. This paper proposes a combination VLC + WiFi based indoor wireless access network structure. Different network architectures are analyzed and optimal scheme is given. Based on...
With the rapid development of renewable energy, the future power system certainly contains a plenty of generators with random output. These uncertain factors usually will aggravate the difficulty of reliability evaluation. On the other hand, the renewable energy generator likes a single wind turbine usually has small capacity. A wind farm has a plenty of wind turbines. The enormous increase of system...
The output of wind power generators and photovoltaic power generators has strong intermittent and randomness and the differences between them are obvious which brings some problems to the planning and operation of power system. This paper build the wind power and photovoltaic units output probability model based on Weibull probability model and Beta probability model considering time-space correlation...
In recent years, the utilization of renewable resources such as wind and solar to generate electrical power has been growing due to the two main driving forces: environmental advantages coupled with financial benefits. Owing to the negligible operating cost, dropping investment and zero-pollution, the renewable energy (RE) technologies have a rapid development. As a result, renewable energy will have...
This paper proposes an interesting three-stage algorithm targeting at highly reliable high dimension composite system reliability evaluation using Importance Sampling (IS). The central idea is at the first stage (the Screening stage) picking out those bottle-neck components which have the most main impact on composite system reliability indexes calculation. The Screening process is specially customized...
Spinning reserve (SR) is an important resource, which is used by system operators to maintain system security and improve operational reliability. A certain capacity of spinning reserve must be configured in every power system. In order to make the optimization of SR more practical, a new model to optimize spinning reserve of power system with transmission line fault is proposed, which is based on...
Dichromats (a human with red-green color blindness considered in this paper) cannot always perceive meaningful visual information due to their deficiencies in eye cells. Stroke information extraction from a color-blindness image (CBI) is presented in order to deliver direct and effective information to dichromats. A CBI is first transformed into the pattern-highlighted image by means of color component...
The fast label-free detections of the extent and degree of cerebral ischemia have been the difficulties and hotspots for precise and accurate neurosurgery. We experimentally demonstrated the terahertz (THz) transmission imaging of the fresh cerebral tissues at different ischemic stages within 24 hours. With a CO2 laser pumped continuous-wave THz imaging system operating at 2.52 THz, THz imaging could...
An attenuated total internal reflection imaging system was demonstrated with continuous terahertz wave for the first time. A drop of water was imaged to validate its efficacy. The approach enables qualitative or even quantitative studies of the surface layer characteristics. The work paves the way for fast terahertz imaging in an in-vivo biomedical diagnosis without complicated sample preparations...
In general, one limitation in current diagnosis approaches is that they could only detect the existing types of faults, while not be able to detect new types of faults. It is difficult to know in advance all fault types and new types of faults may occur in industry. As such, effective detection and diagnosis on new types of faults are important. In this paper, a novel mixed soft&hard assignment...
In internet of vehicles (IOV), on-board Ad hoc network between vehicles is established randomly and freely based on dedicated short range communication technology, enabling the vehicles beyond visual range of drivers and signal transmission range of on-board communication equipment to establish communication connection for transmission and sharing of information and data through single-hop and multi-hop...
A frequency-to-voltage converter (FVC) is designed for directly converting an input radio-frequency to a dc output voltage over a wide microwave frequency range. The proposed circuit consists of a limiting amplifier (LA) for converting input frequency to correspond ac magnitude and a power detector for ac magnitude to dc voltage conversion. Consequently, the circuit converts the signal frequency of...
Variance Minimization (VM) technique is one of the most popular methods for importance sampling (IS), but it has never been successfully applied to composite (generation and transmission) system reliability evaluation due to the difficulty of solving. In this paper, Geometric Programming (GP) is firstly introduced to repeatedly solve the VM optimization model in multi-levels to adaptively obtain the...
Load balancing is one of the critical factors affecting the performance of parallel computing. An improved partitioning strategy is proposed for structured multiblock grids here. The new subgrid-splitting approach, together with a recursive graph-partitioning algorithm, is to seek a good load balancing as less blocks as possible. Two typical applications are implemented to validate the strategy. Results...
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