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The floating offshore wind turbines (FOWTs) have many more advantages than the onshore wind turbines, but they also have more complicated aerodynamic characteristics due to complex platform motions. The research objective of this paper is to investigate unsteady aerodynamic characteristics of a FOWT under the pitch, yaw, and coupled pitch–yaw platform motions using the computational fluid dynamics (CFD) method in the Unsteady Reynolds Averaged Navier-Stokes (URANS) simulations. The pitch, yaw, and coupled pitch–yaw motions are studied separately to analyze the platform motions’ effects on the rotor blade. The accuracy of the numerical simulation method is verified, and the overall performances, including power and thrust, are discussed. In addition, the comparison of total aerodynamic performance, force coefficients at different spans and structural dynamic response is provided. The numerical simulation results show that the platform pitching is the main influencing factor of power fluctuation, and the average thrust values of the pitch, yaw, and coupled motions are consistent regardless of the frequency value. The angle of attack (AOA) of airfoils is much more sensitive to the yaw motion, while the blade normal and tangential forces are mainly affected by pitch motion. As for the structural response, the results suggest that the aerodynamic loads of the wind turbine are more sensitive to the pitch motion, which is confirmed by the thrust force and torque of each blade during the platform motions.

The aeroelastic modeling of Tjaereborg wind turbine blades was performed based on the unsteady Reynolds Averaged Navier-Stokes equations (URANS) combined with Finite Element Method (FEM) in a loosely coupled manner. This method was verified by comparing numerical and experiment results at four axial inflow wind speeds. Furthermore, the aeroelastic performance of Tjaereborg wind turbine under yaw angle of 10°, 30° and 60°were computed and analyzed. The results showed that the average power and thrust of the wind turbine decreased with increasing yaw angle, along with the increasing oscillation amplitude under large yaw angle. The aerodynamic load showed periodic change within one revolution of rotor, resulting in the blade deflection and the strain present considerably asymmetric distributions. The maximum deflection and strain occurred at azimuth angle of about90° and their minimum values occurred at azimuth angle of about 270°. Besides, both the maximum deflection and strain under yaw conditions became larger than those in axial inflow condition do. For Tjaereborg wind turbine, the coupled solver gave a higher average power and thrust than the CFD solver alone. The aerodynamic performances showed more asymmetrical characters under the combined effect of yaw and fluid structure interaction (FSI).

The Nd7.69Fe92.31-xTix (x = 0, 4, 8, 12) alloy were prepared by arc smelting and high energy ball milling method. The morphology and phase structure of the powders were analyzed by Scanning Electron Microscope (SEM), X-ray diffraction (XRD) and the effect of the Ti content on microwave absorbing properties of the powders were measured by a vector network analyzer (VNA). The results reveal that the samples mainly consisted of Nd2Fe17 and α-Fe crystal structure. The minimum absorption peak frequency shifts to lower frequency region firstly and then shifts to higher frequency region with the increasing amount of Ti content. The minimum reflection loss of Nd7.69Fe84.31Ti8 powder is-31.35 dB and the bandwidth of R < -5 dB reach 3.6 GHz when the coating thickness is 2.0 mm. With the increasing of the coating thickness, the minimum reflectivity peak value of the Nd7.69Fe84.31Ti8 moves to lower frequency region and the minimum reflection loss increase firstly and then decrease. And the minimum reflection value of Nd7.69Fe84.31Ti8 alloy can reach to-38.74 dB (microwave absorption rate 99.99%) at 5.68 GHz, and the bandwidth of R < -10 dB reach 1.12 GHz with the best matching thickness of 2.2 mm.

The wake of a wind turbine has substantial influence on the aerodynamic performance of downstream wind turbine. Unsteady numerical simulations are performed in this paper to investigate the wake structure of a three-bladed H-type VAWT (vertical axis wind turbine) and the influence on the aerodynamic performance of downstream wind turbine. A simplified two-dimensional model is used considering the blades are straight. Unsteady Reynolds Averaged Navier–Stokes equations are solved using FlowVision software, which uses dynamic grid method to handle the blade rotation. The SST turbulence model is used for turbulence modeling. The distance between two wind turbines is from 5D to 17D with 2D intervals, where D denotes the wind turbine diameter. The wind speed is 5.07 m/s, corresponding to a tip speed ratio of 2.15. The power coefficients of two wind turbines are compared in detail. The discussions focus on the periodic variations of the aerodynamic performance and flow variables of two turbines with two typical distances, i.e., 7D and 15D, respectively. The simulation results show that the velocity recovery distance needed for a VAWT is usually larger than 15D.

MnAlFe alloy was prepared by the combined use of smelting, high-energy ball milling and tempering heat treatment process. The phase composition and microwave absorbing properties of MnAlFe alloy were investigated by X-ray diffractometer(XRD) and vector network analyzer. The results show that the powders consist of Al8Mn5 single phase with different Fe content; the dielectric loss and the magnetic loss increases with the addition of Fe, the resonant frequency and absorption peak of ε″ and μ″ moves towardslower frequency region simultaneously. The (Al8Mn5)99Fe exhibits preferably comprehensive microwave absorbing properties in the range of 6-18 GHz. The value of the minimum reflectivity and absorption peak frequency with the coating thickness of 1.5 mm, are -23.1 dB, 15.04 GHz respectively. Owing to the wide applications of electromagnetic waves in the range of 1–4 GHz for mobile phone, local area network, radar systems and so on over the past few decades, the serious problems of the electromagnetic interference and electromagnetic compatibility have become increasingly prominent in recent years. Microwave absorbing materials, which possess special performance for absorbing electromagnetic wave, have been applied in both civil and military fields and play an important role in camouflage technology. In military field, stealth technology to reduce and eliminate the electromagnetic radiation and electromagnetic interference resulting from the broad applications of various kinds of electronic and microwave instruments, stealth technology plays an important strategic role in the wars in future[1-2]. The microwave absorbing materials can be used to reduce radar cross section for military use. For this reason, the microwave absorbing material is vitally important for both civil and military fields[3-7]. In view of this utilization, excellent microwave absorbing materials should exhibit strong microwave absorption properties over a wide frequency range and need to be thin and light in weight. It has an important meaning to the application of magnetic microwave absorbing materials. MnAl alloy can be used as microwave absorbent. It has properties such as light in weight, good thermal stability and corrosion resistance[8-11]. But as permanent magnets, MnAl has shortcomings such as their difficulties of fabrication and high costs that prevent them from being used as permanent magnets. A great value would be brought to either theory or practice through proper treatments as further improvement in properties. In this paper, we will discuss the effects of changing relative content of Fe on absorption properties of Al8Mn5 alloy.

The operation of the wind turbines downstream is affected by the wake of the wind turbines upstream. Wind turbine wake flow is investigated by applying the actuator disc (AD) method. The modified k-ε turbulence model is proposed by using both the turbulent kinetic energy source term and the dissipation rate source term to improve the standard k-ε turbulence model for coordinating the generation and the dissipation of the turbulent kinetic energy. The dissipation rate parameter C4ε that obeys a parabolic distribution is used, based on theoretical analysis. The force distributed on the AD is also used instead of a constant, as used in the classical AD method. The simulation results were consistent with the measurements that correspond to different kinds of wind turbines and conditions. The nacelle and the inflow turbulence intensity have great influences on accurately simulating the wake, so it is necessary to imitate the rotor along with the nacelle and accurately measure the inflow turbulence intensity.

In a smart grid, electricity energy demands requested from down-stream sectors continuously increase. One way to meet the energy demands is utilizing a Non-Intrusive Load Monitoring (NILM)-style system to monitor and manage residential and commercial electrical appliances in respond to demand response programs. NILM is as an electricity energy audit to energy-saving issues.This paper aims at developing an NILM identification considering the influence of voltage variations. An NILM system normally consists of "Data Acquisition", "Event Detection and Feature Extraction", and "Load Classification." The goal of load classification in NILM is to identify the operation ON/OFF status of individual household appliances. The k-Nearest Neighbors Classifier is used as the load classifier of the NILM. In NILM, measured physical phenomena, voltage signals/power profiles, to load classification for long-term load monitoring vary. The variations affect the identification performance. In this paper, a cross-validation strategy is conducted and used to deal with sampled data with systematic errors from classified loads. Different types of loads are used to verify the influence of the voltage variations to load identifications. As the experimentation reported in this paper shows, a satisfactory recognition rate of 97.60% to the NILM load identification addressed in this paper is achieved. The proposed NILM system is able to classify loads with proper robustness.

This paper mainly focuses on the modeling and simulation of the doubly fed induction generator (DFIG) based wind turbine generation system. In this paper, a new method which combines the mechanical part and electrical part is presented to model the wind turbine generation system. The turbine rotor blade is modeled by the lifting line model and the aerodynamic forces are solved by the improved free vortex wakes method with the supplementary of two dimensional aerodynamic data (three dimensional corrected). The control system of pitching and generator with voltage oriented control (VOC) are established in Matlab/Simulink. The drive train is also modeled with two mass model. In order to realize the coupling computation of the wind turbine model, a data link is built to transfer the parameters between aerodynamic part and electrical part. In this way, the interaction between turbine rotor and generator could be predicted. The validations are firstly made to ensure the reliability of the model. Then the performance of a 1.5 MW wind turbine is investigated with this integrated model under different wind and symmetrical grid voltage dip condition.

To be able to more accurate analysis aerodynamic characteristic variation under yaw of NREL Phase VI wind turbine. The influence of yaw on the aerodynamic characteristic by using a three-dimensional unsteady CFD methods based sliding mesh in this paper. To flow, the overall performance and Cp of the three-dimensional flow numerical simulation were compared with experimental results with the same wind speeds to confirm the reliability of the model at a given axial wind speed conditions. In the yaw conditions, the effect of yaw on the aerodynamic performance of wind turbine blades, changing law and reveal the aerodynamic performance is in the flow details and rules in different azimuth.

In order to accurately analysis the aerodynamic characteristic variations of wind turbines under shear, the influence of axial and shear on the aerodynamic characteristic of a horizontal-axis wind turbine is simulated in this paper by using a sliding grid method based on FlowVision. By using the TJÆREBORG wind turbine as the object of study, a three-dimensional model of a uniform wind flow can be created. The CFD calculation results, the experimental results and the Bladed results can be used to confirm the reliability of the model. In order to investigate the effect of wind shear with regard to three-dimensional unsteady flow characteristics and a three-dimensional flow field in a wind turbine impeller, an analysis of wheel wind speed of 11m/s and an investigation of the influence of wind shear on turbine performance are carried out.

According to the characteristics of cage wind turbines’ dynamic characteristics which change following the wind speed changes, the dynamic mathematical models of cage wind turbines major subsystems have been established, including the aerodynamic subsystem model, drive train subsystem model and generator subsystem model. Then these nonlinear dynamic models with time-varying parameters have been integrated and linearized to obtain the whole linear time-varying parameters dynamic mathematical model. To take the 2MW cage wind turbines wind turbine as example, the proposed model is validated by the study on the dynamic characteristics of cage wind turbines with wind speed variation , and the results show that the proposed model could provide a theoretical support for optimal control of the cage wind turbines.

In this paper, non-deterministic CFD (computational fluid dynamics) simulations have been performed to investigate the uncertain effects of stochastic boundary conditions on the aerodynamic performance of wind turbines. A NIPRC (non-intrusive probabilistic collocation) method is employed, which is coupled with a commercial flow solver. A 2D (two-dimensional) airfoil case is used to validate the non-deterministic simulation, where the angle of attack is considered as an uncertain parameter in a Gaussian distribution. The simulation results are compared with Monte Carlo simulation results. Based on the validation, non-deterministic CFD simulations were performed on a 3D (three-dimensional) wind turbine blades case, where the wind speed is considered as an uncertain parameter. The discussions mainly focus on the total performance variations and the uncertainty propagation in the fluid field. The simulation results show that the input uncertainty of the inlet velocity results in a high variation zone in the pressure distribution near the blade root, and which decreases from the root to the tip. With the wind speed increases, flow separation is observed. The separation vortex regions correspond to the maximum variation area, and the maximum variation extends to the trailing edge even to the whole suction side.

The aerodynamic performance and the bypass flow field of a vertical axis wind turbine under self-starting are investigated using CFD simulations in this paper. The influence of pitch angle variations on the performance of the wind turbine during self-starting is presented. A two-dimensional model of the wind turbine with three blades is employed. A commercial software FlowVision is employed in this paper, which uses dynamic Cartesian grid. The SST turbulence model is used for turbulence modeling, which assumes the flow full turbulent. Based on the comparison between the computed time-dependent variations of the rotation speed with the experimental data, the time-dependent variations of the torque are presented. The characteristics of self-starting of the wind turbine are analyzed with the pitch angle of 0o、-2oand 2o. The influence of pitch angle variations on two-dimensional unsteady viscous flow field through velocity contours is discussed in detail.

In this paper, a dynamic stall control scheme for vertical-axis wind turbine (VAWT) based on pulsed dielectric-barrier-discharge (DBD) plasma actuation is proposed using computational fluid dynamics (CFD). The trend of the wind turbine power coefficient with the tip speed ratio is verified, and the numerical simulation can describe the typical dynamic stall process of the H-type VAWT. The tangential force coefficient and vorticity contours of the blade are compared, and the regular pattern of the VAWT dynamic stall under different tip speed ratios is obtained. Based on the understanding the dynamic stall phenomenon in flow field, the effect of the azimuth of the plasma actuation on the VAWT power is studied. The results show that the azimuth interval of the dynamic stall is approximately 60° or 80° by the different tip speed ratio. The pulsed plasma actuation can suppress dynamic stall. The actuation is optimally applied for the azimuthal position of 60° to 120°.

In the present paper, the non-intrusive Probabilistic Collocation (NIRPC) method is introduced in detail and used to simulate the effects of tip clearance uncertainty on the aerodynamic performance of NASA Rotor 37, which is combined with a commercial CFD software. The tip clearance height is supposed to be a stochastic variable in Beta distribution with four schemes of uncertainty in the random height of the plain tip clearance, the leading edge, the trailing edge and both the leading and trailing edges, respectively. The statistical properties of total performance of the rotor and flow structure within the blade passage in different flow conditions are analyzed. The results show that the Std. of total performances caused by the uncertain plain tip clearance decreases with reducing of the outlet pressure. The maximum of the standard deviation of Mach number appears in the regions where the leakage flow, the shock wave and the separation flow locate, which decreases from the tip to the hub. When the tip clearance is linear distributed, the uncertainty of tip clearance height at the leading edge is the main factor under high mass flow conditions. With the mass flow reaches to choking point, the Std. of total performances caused by the uncertainty of tip clearance height at the trailing edge drops sharply.

Vortex generators (VGs) are an effective way to control flow separation in wind turbine. To understand the mechanism of VGs controlling flow separation, the flow field around airfoil Du97W300 with VGs was simulated and analyzed with CFD tools, and this numerical method is validated through the comparison between the numerical results and the experimental results. Furthermore, the flow fields around airfoil equipped with four different types of VGs are calculated and analyzed. The results show that the helical vortex induced by counter-rotating VGs develop approximately along streamwise direction; these types of VGs can cause a delay in stall and enhance the maximum airfoil lift coefficient. However the helical induced vortex actuated by the co-rotating VGs develop nearly along vortex generator direction and cannot cause a delay in stall effectively. In the counter-rotating VGs, the Q integration (the character parameter of induced vortex) of rectangular is twice of the triangle, and the Q integration of the forward triangle is almost equal to the backward triangle VGs.

The present study focuses on the experimental and numerical investigation of heat transfer performance downstream of the cooling holes on a flat plate with zero streamwise pressure gradient. The experiment was conducted in a low speed wind tunnel. The holes are circular in either straight or curved shape with an angle of 90°. In the experiments, both local and transverse averaged cooling effectiveness and heat transfer coefficient in the surface are studied for single and multiple holes in a row over a range of blowing ratio from 0.5 to 1.22 for single hole and 0.32–1.18 for multiple holes. Surface temperatures downstream of the injection were measured by means of thermal liquid crystals (TLC) and its associated camera system. Numerical simulation were perform for single hole at blowing ratios 0.51 and 1.04 by using Detached Eddy Simulation (DES) method based on S–A one equation turbulence model. In comparison with the straight hole, the curved one shows better overall performance expressed by net heat flux reduction (NHFR) based on both the experimental and numerical results, such as a better transverse spreading, higher cooling effectiveness and an increased local heat transfer coefficient are concluded for the curved hole.

The aerodynamic performance of a compressor is highly sensitive to uncertain working conditions. This paper presents an efficient robust aerodynamic optimization method based on non-deterministic computational fluid dynamic (CFD) simulation and Multi-Objective Genetic Algorithm (MOGA). A NonIntrusive Polynomial Chaos method is used in conjunction with an existing well-verified CFD module to quantify the uncertainty propagation in the flow field. This method is validated by comparing with a Monte Carlo (MC) method through full three dimensional CFD simulations on an axial compressor (NASA rotor 37). Based on the validation, the non-deterministic CFD is coupled with a surrogate-based MOGA to search for the Pareto front. A practical engineering application is implemented to the robust aerodynamic optimization of rotor 37 under random outlet static pressure. Two curve angles and two sweep angles at tip and hub are used as design variables. Convergence analysis shows that the surrogate-based MOGA can obtain the Pareto front properly. Significant improvements of both mean and variance of the efficiency are achieved by the robust optimization. The comparison of the robust optimization results with that of the initial design and a deterministic optimization demonstrate that the proposed method can be applied to turbomachinery successfully. Copyright c © 2011 John Wiley & Sons, Ltd.

In order to assess the influences of curved hole passage on cooling effectiveness and flow structure of turbine blade leading edge, the detached eddy simulation is applied to numerically investigate the AGTB turbine cascade under the condition of global blowing ratio M=0.7. The straight or curved cooling holes are located at either the pressure or suction side near the leading edge. The analysis and discussion focus on the local turbulence structure; influence of pressure gradient on the structure, and distribution of cooling effectiveness on the blade surface. The numerical results show that cooling hole with curved passage could bring positive impact on the increase of the local cooling effectiveness. On the suction side, the increased cooling effectiveness could be about 82% and about 77% on the pressure side, compared to the conventional straight hole.

The buildings of domestic wear the upper floors and an underground in-depth reconciliation tendency to do and the possibility of fire occurrence at the time of formation accident is coming to be high. Therefore will be scattered to various place and is established and prevention of disaster information of the receiver which will integrate there is a necessity which will manage. In this paper away where each receiver is installed in the fire for the remote monitoring and controld able to connect to the Internet and fiber optic cable that can be networked fire receiver and control desk was constructed. Between each device can be used by the fire, and more depending on the status of monitoring and alarm, control and maintenance can be performed to develop an integrated management system. The system is evaluated by the criteria of the KFI, and for each segment of the signal propagation time to perform experiments confirmed the reliability of the performance.

In the trend of miniaturization narrow frame and fine wiring structure,the TFT-LCD tends to developing for large margin of design and high real substrate utilization rate.The passivation layer deposit parameters were changed to decrease the size of via hole which connected the pixel electrode and drain electrode were studied.Through the experiments design of changing main parameters to minimize via hole of passivation layer(haze,undercut,Top-PVX deposit thickness,Top-PVX deposit pressure),a solution to minimize the via hole about 20%~30% without changing the etch conditions was found.The electronic parameter measurement was evaluated(Ion,Ioff,Vth,Mobility) and finally one better solution to minimize via hole size was obtained.Therefore,the products quality was improved also.

The NdFe magnetic absorbing materials were prepared by rapid solidification and high-energy ball milling method. The effect of high-energy ball milling on particle morphology, organizational structure and microwave absorbing properties of NdFe magnetic absorbing materials were analyzed with the aid of X-ray diffractometer, scanning electron microscope and vector network analysis. The results show that the Nd2Fe17 and α-Fe phase are refined, the particles become smaller and thinner; the span-ratio of the particles increases along with time during the process of high-energy ball milling; and meanwhile, the frequency of absorbing peak reduces. The absorbing bandwidth broadens as the increase of the time of ball milling, except that of 48h.The minimum reflectance of the powder decreases from -22dB to - 44dB under the circumstances that the time of high energy ball milling reaches 48h and the thickness of the microwave absorbing coating is 1.5mm. But it rebounds to about - 6dB when the time of ball milling reaches 72h.

The influence of wind turbine airfoil trailing edge thickness on aerodynamics and aerodynamic noise characteristics was studied using the computational fluid dynamics (CFD)/ Ffowcs Williams&ndash, Hawkings (FW&ndash, H) method in the present work. First, the airfoil of a DU97-W-300-flatback airfoil was chosen as the research object, and numerical method validation was performed. Three kinds of turbulence calculation methods (unsteady Reynolds average Navier-Stokes (URANS), detached eddy simulation (DES), and large eddy simulation (LES)) were investigated in detail, and three sets of grid scales were used to study the impact of the airfoil on the aerodynamic noise. Secondly, the airfoil trailing edge thickness was changed, and the impact of trailing edge thickness on aerodynamics and aerodynamic noise was investigated. Results show that three kinds of turbulence calculation methods yield the same sound pressure frequency, and the magnitude of the sound pressure level (SPL) corresponding to the mean frequency is almost the same. The calculation of the SPL of the peak value and the experimental results can match well with each other, but the calculated core frequency is slightly lower than the experimental frequency. The results of URANS and DES are closer to each other with a changing trend of SPL, and the consequences of the DES calculation are closer to the experimental results. From the comparison of two airfoils, the blunt trailing edge (BTE) airfoil has higher lift and drag coefficients than the original airfoil. The basic frequency of lift coefficients of the BTE airfoil is less than that of the original airfoil. It is demonstrated that the trailing vortex shedding frequency of the original airfoil is higher than that of the BTE airfoil. At a small angle of attack (AOA), the distribution of SPL for the original airfoil exhibits low frequency characteristics, while, at high AOA, the wide frequency characteristic is presented. For the BTE airfoil, the distribution of SPL exhibits low frequency characteristics for the range of the AOA. The maximum AOA of SPL is 4&deg, and the minimum AOA of SPL is 15&deg, while, for the original airfoil, the maximum AOA of SPL is 19&deg, and the minimum AOA is 8&deg, For most AOAs, the SPL of the BTE airfoil is larger than that of the original airfoil.

Reynolds number has significant impact on the aerodynamic performance of axial turbines. The internal flow within the stator of a low pressure turbine could be all laminar when the inlet Reynolds number is very low, and large flow separation may occur on the suction surface of the blade. The separated laminar boundary layer and the wake have strong unsteady interactions with the main flow in rotor passages. In order to investigate the laminar flow separation and the interaction, both laminar flow simulation and detached eddy simulation (DES) have been performed on a low speed axial turbine under a very low Reynolds number condition in this paper. For comparison, fully laminar modeling, transitional modeling and fully turbulent modeling are performed, also. The comparison between the computational results and the experimental results shows that both the laminar modeling and transition modeling can capture the laminar separation on the suction side of the stator blade accurately. The separation region locates in a thin zone strengthening from the blade tip to the hub, which is induced by the tip passage vortex. The separation generates a high turbulence intensity zone at the stator outlet. However, this zone in laminar simulation is smaller than that in the experimental due to the absence of turbulence disturbances. Fully turbulent modeling predicts a delayed separation and a smaller separation region. Detached eddy simulation is performed for single stator row, which gives better predictions for both the flow separation and high turbulent zone. The detailed flow structures of the secondary vortices of the stator, the rotor passage vortex and the tip leakage vortex are illustrated. The simulation results show that the laminar separation has obvious three dimensional behaviour. The radial movement of the horse shoe vortex is the main disturbance to the flow separation.Copyright © 2015 by ASME

Wind turbine aerodynamic-mistuning phenomenon during the operation may cause great harm. This article is based on sliding mesh technique of three dimensional Unsteady CFD method,taking NREL Phase VI wind turbine as an example,study the pneumatic performance of wind turbine under the axial-flow condition ,and compare with the experimental data.After validate the accuracy of the method,according to the effect of yaw and wind shear on the wind turbine aerodynamicmistuning ,researched have been conducted: In a wind shear condition,the aerodynamic performance after the blade rotating one circle have been calculated in the different wind profile index.Because of the shear wind velocity, Airfoil load and flow parameters fluctuate approximately like the patterm of cyclical cosine function with the change of azimuth.And with wind profiles index and spanwise position increases, impulse amplitudes have been also increased;Under the circumstances of the constant wind speed and variable yaw angle , The aerodynamic power decreases with the increase of the yaw angle There are also some big differences at different azimuth angle of blade section. Keywords-yaw;aerodynamic;mistuning;shear;wind turbine

In order to improve the accuracy of electro-optical tracking system, a novel feed forward-IMC controller based on Internal Model Control has been designed and made the simulation on the system. The simulation result showed that the feed forward-IMC controller can meet the need of high accuracy of electro-optical tracking system and it also have good feasibility and robustness. It has the better tracking performance in comparison with other high accuracy controller. It is able to converge efficiently and tracking accuracy can be increased several times.

Due to the problems of target motion parameter can not be directly predict and predicting accuracy reduced caused by miss distance in TV tracking system,an uncertain factor γ was introduced in the measurement equation, and it's probability to represent the system delay volume. At the same time according to the theory of Unscented Kalman filtering,the calculation algorithm of state estimation in nonlinear system with measurement delay is given(called measurement delay Unscented Kalman filter). And then,it is applied in equivalent compound control of TV tracking system. The simulation results show that introduction uncertain factor in measurement equation for describing measurement delay is valid, and can greatly reduced predicting error and tracking.

Electro-optical tracking devices in the television or infrared automatic tracking system, miss distance lag system overshoot increased, lengthened the transitional period, affecting the stability control system and reduce the tracking precision.Feedforward control technology is to improve the tracking accuracy and to maintain the stability of the system an effective way. The speed of introduction of the forecast information as feedforward control signals constitute the equivalent composite control can be approximated to achieve feedforward control technology. The filter for the synthesis of the target location information with lag, interference is the key problem of compound control technology. In order to obtain the high-precision forecasting velocity of moving target, Kalman filter with the measurement lag is designed. Forecasting velocity of moving target can obtain by forecasting the synthesis target position with measurement lag. The actual Electro-optical tracking equivalent compound control system simulation and experimental results show that the velocity of moving target can be forecasted by using the methods and tracking precision can be improved in servo-control system.

Flow structures in a turbine cascade with film cooling injections at the blade leading edge are investigated numerically for three cooling models of slots, straight cylindrical and spanwise inclined cylindrical holes under various blowing ratios, 0, 0.5, 0.7, 1.1, and 1.5. The numerical simulations are well compared with experiment results of static pressure and oil film visualization of blade surfaces. Discussions are mainly focused on the 3D flow structures within a blade passage. The results show that the 3D flow and energy loss production is greatly affected by the cooling injections, especially near the blade pressure surface.Copyright © 2008 by ASME

In order to get more insight into the influence of blade lean angle on the flow performance in the design process of a one-stage turbine with large diameter/height ratio, a through-flow tool of AxSTREAM is used to make the investigation. Based on the optimization of design, stage performances of variable working conditions for twenty-one lean angles in stator and in rotor respectively are simulated through DoE analysis. Some results for five typical lean angles are compared with the data of a 3D CFD simulation performed with FINE/TURBO software. The changes of reaction and static pressure distributions under different lean angles are presented, with discussion and analysis of the influence of parameters, such as diameter/height ratio and rotation speed, on the best lean angle.

This paper presents the CFD simulations of a high speed centrifugal compressor impeller using the NUMECA Fine/Turbo software with the one equation turbulence model of Spalart-Allmaras. The simulations are validated via comparison with the experimental data. The computational grid densities are changed with the impeller tip size and a grid independent study is carried out. The flow physics of the compressor impeller is numerically studied in details, in particular, the formation of shocks and their effects on the 3D flow and the secondary flow structure are analyzed at different operation conditions, with comparison to low speed machines. It is found that the energy loss production is greatly affected by the shock waves and their interaction with the boundary layers in the inducer portion, while in the other portion, the secondary flow structure is globally the same as those in low speed machines.Copyright © 2005 by ASME

Ga-doped ZnO (GZO) films were deposited onto low-temperature-grown (LTG) GaN/i-GaN (PD-I) and i-GaN (PD-II) epitaxy layers to form Schottky barrier UV band-pass photodetectors (PDs). The UV PDs exhibited a narrow band-pass spectral response ranging from 330 to 380 nm. It was also found that by using an LTG GaN layer on top of conventional nitride-based UV PDs, the leakage current was significantly reduced and a much larger photocurrent-to-dark-current contrast ratio was achieved. The short-wavelength cutoff at around 330 nm can be attributed to the marked absorption of the GZO top contact layer. The zero-bias peak responsivities were estimated to be 0.13 and 0.08 A/W at 360 nm for PD-I and PD-II, respectively. When the reverse bias was below -10 V, the dark current of PD-I was considerably below 20 pA.