Zhan Wang¹, Liang Li^2,*, Long Wang¹, Weidong Zhu³, Yinghui Li⁴, Echuan Yang⁵

Energy Engineering, Vol.121, No.10, pp. 2981-3000, 2024, DOI:10.32604/ee.2024.048161 - 11 September 2024

Abstract A dynamic pitch strategy is usually adopted to improve the aerodynamic performance of the blade of a wind turbine. The dynamic pitch motion will affect the linear vibration characteristics of the blade. However, these influences have not been studied in previous research. In this paper, the influences of the rigid pitch motion on the linear vibration characteristics of a wind turbine blade are studied. The blade is described as a rotating cantilever beam with an inherent coupled rigid-flexible vibration, where the rigid pitch motion introduces a parametrically excited vibration to the beam. Partial differential equations More > Graphic Abstract

Husam Rashid Hudear^*, Saad Najeeb Shehab

Frontiers in Heat and Mass Transfer, Vol.21, pp. 367-383, 2023, DOI:10.32604/fhmt.2023.042639 - 30 November 2023

Abstract This paper presents a numerical emulation study of heat transmission through tube banks in three-dimensions. Staggered configuration is displayed by fluid dynamics using computer programs (CFD) software (ANSYS fluent). The computer model is used to predict the values of the Nusselt number when changing the values of heat flux and longitudinal pitch. The longitudinal pitch (SL/D) of 1.3, 1.8, and 2.4 mm. The transverse pitch (ST/D) of 1.5 mm, and also considered Reynolds numbers 10000, 13000, 17000, and 190000. The staggered configuration of the tube bundle is demonstrated to investigate the impact of this arrangement More >

Changyao Chen¹, Jialei Song^1,*, Ling Yin¹, Yizhe Li², Zheng Yuan², Yuhan Li³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.25, No.1, pp. 1-1, 2023, DOI:10.32604/icces.2023.09859

Abstract Bird can switch between high maneuverability and high stability due to its ability to substantially morph wings and tail. Tail as an auxiliary lift surface, plays an important role on lift and drag production and also significantly affects the longitudinal stability. In this study, we reconstruct a high-fidelity barn owl model using the point cloud of its surface obtained from high-speed photogrammetry, and simulate the fluid dynamics using a commercial software. By virtually manipulating the tail to a series of postures, we analyze the aerodynamics and static stability for each tail posture, investigating the strategy More >

Zhiwei Lin¹, Tianding Chen^1,*, Yingtao Jiang², Hui Wang¹, Shuqin Lin¹, Ming Zhu²

Intelligent Automation & Soft Computing, Vol.36, No.2, pp. 2145-2164, 2023, DOI:10.32604/iasc.2023.035555 - 05 January 2023

Abstract Directly applying the B-spline interpolation function to process plate cams in a computer numerical control (CNC) system may produce verbose tool-path codes and unsmooth trajectories. This paper is devoted to addressing the problem of B-spline fitting for cam pitch curves. Considering that the B-spline curve needs to meet the motion law of the follower to approximate the pitch curve, we use the radial error to quantify the effects of the fitting B-spline curve and the pitch curve. The problem thus boils down to solving a difficult global optimization problem to find the numbers and positions… More >

Anfeng Zhu¹, Qiancheng Zhao^1,*, Lin Gui¹, Tianlong Yang¹, Xuebing Yang²

Energy Engineering, Vol.120, No.2, pp. 425-444, 2023, DOI:10.32604/ee.2023.023049 - 29 November 2022

Abstract To ensure wind turbine (WT) safe operations and improve the utilization rate of wind energy, effective evaluation of the operation state of the pitch system is critical. Therefore, a new method was proposed to evaluate the operation state of the pitch system of WT based on fuzzy comprehensive evaluation. Firstly, based on SCADA data, the working state of the pitch system under rated power state and power state of WT were analyzed. Secondly, through the analysis of characteristic parameters and physical mechanism of the pitch system, the consistency principle of characteristic parameters, the stability principle… More >

Fei Zhou, Yu Zhou^*, Xuemin Ye

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.4, pp. 1025-1037, 2022, DOI:10.32604/fdmp.2022.020196 - 06 April 2022

Abstract Taking a two-stage variable-pitch axial fan as the research object, five schemes, including a single counter-flow rib layout grooved tip, are numerically simulated using the fluent software. The results indicate that, compared with the original blade tip, the total pressure rise and efficiency of the four proposed schemes have been improved to various degrees, with Scheme 4 (groove tip with double counterflow ribs) displaying the best performances. The total pressure and efficiency are increased by 113.44 Pa and 0.955%, respectively. The blade tip leakage flow is reduced to varying degrees under different schemes, according to the More >

Ibrahim M. Mehedi^1,2,*, Ubaid M. Al-Saggaf^1,2, Mahendiran T. Vellingiri¹, Ahmad H. Milyani¹, Nordin Bin Saad³, Nor Zaihar Bin Yahaya³

CMC-Computers, Materials & Continua, Vol.71, No.2, pp. 4001-4017, 2022, DOI:10.32604/cmc.2022.021981 - 07 December 2021

Abstract In recent times, wind energy receives maximum attention and has become a significant green energy source globally. The wind turbine (WT) entered into several domains such as power electronics that are employed to assist the connection process of a wind energy system and grid. The turbulent characteristics of wind profile along with uncertainty in the design of WT make it highly challenging for prolific power extraction. The pitch control angle is employed to effectively operate the WT at the above nominal wind speed. Besides, the pitch controller needs to be intelligent for the extraction of… More >

Ravindra Birajdar^1,*, Appasaheb Keste², Shravan Gawande²

Sound & Vibration, Vol.55, No.4, pp. 305-327, 2021, DOI:10.32604/sv.2021.017000 - 18 October 2021

Abstract The objective of the study is to find the tolerance on vane pitch dimensions of a Vertical Turbine (VT) pump impeller. For this purpose, the study is divided into two parts viz. to find the critical hydraulic eccentricity of a VT pump impeller by way of numerical simulations and design of experiments to find the vane pitch tolerance using critical hydraulic eccentricity. The effect of impeller vane pitch deviations on hydraulic unbalance is examined for a vertical turbine pump using Design of Experiments (DOE). A suitable orthogonal matrix has been selected with vane pitch at More >

Yilin Hu¹, Yan Xie², Bo Li^3,*, Yiqiang Jiang¹, Fu Bao¹

Energy Engineering, Vol.118, No.4, pp. 911-929, 2021, DOI:10.32604/EE.2021.014759 - 31 May 2021

Abstract Wind turbine employs pitch angle control to maintain captured power at its rated value when the wind speed is higher than rated value. This work adopts a perturbation observer based sliding-mode control (POSMC) strategy to realize robust variable-pitch control of permanent magnet synchronous generator (PMSG). POSMC combines system nonlinearities, parametric uncertainties, unmodelled dynamics, and time-varying external disturbances into a perturbation, which aims to estimate the perturbation via a perturbation observer without an accurate system model. Subsequently, sliding mode control (SMC) is designed to completely compensate perturbation estimation in real-time for the sake of achieving a More >

Shahid Ali Mahar¹, Mumtaz Hussain Mahar¹, Javed Ahmed Mahar¹, Mehedi Masud², Muneer Ahmad³, NZ Jhanjhi^4,*, Mirza Abdur Razzaq¹

Intelligent Automation & Soft Computing, Vol.29, No.1, pp. 183-197, 2021, DOI:10.32604/iasc.2021.015755 - 12 May 2021

Abstract Speech signal analysis for the extraction of speech elements is viable in natural language applications. Rhythm, intonation, stress, and tone are the elements of prosody. These features are essential in emotional speech, speech to speech, speech recognition, and other applications. The current study attempts to extract the pitch and duration from historical Sindhi sound clips using the functional contours model’s superposition. The sampled sound clips contained the speech of 273 undergraduates living in 5 districts of the Sindhi province. Several Python libraries are available for the application of this model. We used these libraries for… More >