Coanda effect of a propeller airflow and its aerodynamic impact on the thrust

IF 0.7 Q4 MECHANICS

Journal of Fluid Science and Technology Pub Date : 2020-01-01 DOI:10.1299/jfst.2020jfst0016

Y. Naka, Akira Kagami

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引用次数: 2

Abstract

The aerodynamic performance of the multi-rotor drone under the wall proximity has been investigated by experiment and numerical simulation. The propeller airflow along with the wall deflects toward the wall due to the Coanda effect, and it yields a negative impact on the aerodynamic performance. The present study aims to reveal the link between the propeller thrust and the propeller airflow under different wall proximity conditions. The deflection of the flow is confirmed by the flow visualization, and the wall pressure exhibits the signature of flow attachment both in the profiles of the mean and the fluctuation. The force measurement indicates that the degradation of the thrust is significant enough to affect the stability of the drone body. A possible reason of the decrease in thrust is found in the streamwise velocity distribution. The velocity distributions obtained by the numerical simulation indicate that the swirling motion is significantly suppressed due to the wall proximity effect. Moreover, the pressure distribution on the propeller surface explains the decrease of the thrust. The magnitude of the pressure difference becomes smaller when the propeller blade approaches very close to the wall.

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螺旋桨气流的康达效应及其对推力的气动影响

通过实验和数值模拟研究了多旋翼无人机在接近壁面条件下的气动性能。由于康达效应，螺旋桨气流沿壁面向壁面偏转，对气动性能产生负面影响。本研究旨在揭示不同壁面接近条件下螺旋桨推力与螺旋桨气流之间的关系。流动显示证实了流动的偏转，壁面压力在平均曲线和波动曲线上都表现出流动附着的特征。力测量结果表明，推力的衰减足以影响无人机机体的稳定性。推力减小的一个可能原因是沿流的速度分布。数值模拟得到的速度分布表明，壁面接近效应显著抑制了旋流运动。此外，螺旋桨表面的压力分布也解释了推力减小的原因。当螺旋桨叶片非常接近壁面时，压差的大小变小。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Fluid Science and Technology MECHANICS-

CiteScore

1.00

自引率

12.50%

发文量

期刊介绍： Journal of Fluid Science and Technology (JFST) is an international journal published by the Fluids Engineering Division in the Japan Society of Mechanical Engineers (JSME). JSME had been publishing Bulletin of the JSME (1958-1986) and JSME International Journal (1987-2006) by the continuous volume numbers. Considering the recent circumstances of the academic journals in the field of mechanical engineering, JSME reorganized the journal editorial system. Namely, JSME discontinued former International Journals and projected new publications from the divisions belonging to JSME. The Fluids Engineering Division acted quickly among all divisions and launched the premiere issue of JFST in January 2006. JFST aims at contributing to the development of fluid engineering by publishing superior papers of the scientific and technological studies in this field. The editorial committee will make all efforts for promoting strictly fair and speedy review for submitted articles. All JFST papers will be available for free at the website of J-STAGE (http://www.i-product.biz/jsme/eng/), which is hosted by Japan Science and Technology Agency (JST). Thus papers can be accessed worldwide by lead scientists and engineers. In addition, authors can express their results variedly by high-quality color drawings and pictures. JFST invites the submission of original papers on wide variety of fields related to fluid mechanics and fluid engineering. The topics to be treated should be corresponding to the following keywords of the Fluids Engineering Division of the JSME. Basic keywords include: turbulent flow; multiphase flow; non-Newtonian fluids; functional fluids; quantum and molecular dynamics; wave; acoustics; vibration; free surface flows; cavitation; fluid machinery; computational fluid dynamics (CFD); experimental fluid dynamics (EFD); Bio-fluid.