Flow fields and losses downstream of an ultra-highly loaded turbine cascade with bowed blades

Tan, Chunqing; Zhang, H L; Chen, Haisheng; Yamamoto, Atsushi

doi:10.1177/09576509jpe989

Cited by 4 publications

(1 citation statement)

References 28 publications

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“…For example, the increased positive bowing angle would lead to thicker boundary layer and higher energy loss near the midspan, while the increased negative bowing angle would lead to more instable flow field and higher energy loss near the suction–endwall corner. 17,18 Therefore, the studiers would have to limit the side effects of the conventional bowing design until the negative influences could be reasonably ignored.…”

Section: Introductionmentioning

confidence: 99%

The compound bowing design in a highly loaded linear cascade with large turning angle

Xue

Wang

Luo

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part G:

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Numerical simulation was carried out to study the influences of blade-bowing designs based on a highly loaded cascade with large turning angle, while the compound bowing design showed much lower endwall loss than the conventional design in this study. Generally, it showed that the increased turning angle would strengthen the adverse pressure gradient on the suction surface, so the side effect of negative blade bowing angle would be enhanced because of the reduced flow filed stability near suction–endwall corner. However, the positive corner bowing angle that applied in the compound bowing design would enhance the flow field stability near the suction–endwall corner by adjusting spanwise pressure gradient and velocity triangle, so the side effect of negative blade bowing angle would be suppressed and lead to weaker secondary flow. In detail, the blade bowing angle (as well as the corner bowing angle in the conventional bowed cascades) was varied from −5° to −30° in this study, while the reductions of the loss coefficient in the compound bowed cascades were about 0.662.16 times higher (the absolute differences were about 0.0067 0.0097) than the corresponding conventional bowed cascades. Moreover, the Reynolds number and Mach number at the outlet plane were kept at 2.4 × 105 and 0.6, respectively, during the bowing design to ensure the comparability.

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Section: Introductionmentioning

confidence: 99%

The compound bowing design in a highly loaded linear cascade with large turning angle

Xue

Wang

Luo

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part G:

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The influence of gravimetric moisture content on studded shoe–surface interactions in soccer

Clarke

Carré

2016

Sports Eng

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It is desirable for the studs of a soccer shoe to penetrate the sport surface and provide the player with sufficient traction when accelerating. Mechanical tests are often used to measure the traction of shoe-surface combinations. Mechanical testing offers a repeatable measure of shoe-surface traction, eliminating the inherent uncertainties that exist when human participant testing is employed, and are hence used to directly compare the performance of shoe-surface combinations. However, the influence specific surface characteristics has on traction is often overlooked. Examining the influence of surface characteristics on mechanical test results improves the understanding of the traction mechanisms at the shoesurface interface. This allows footwear developers to make informed decisions on the design of studded outsoles. The aim of this paper is to understand the effect gravimetric moisture content has on the tribological mechanisms at play during stud-surface interaction. This study investigates the relationships between: the gravimetric moisture content of a natural sand-based soccer surface; surface stiffness measured via a bespoke impact test device; and surface traction measured via a bespoke mechanical test device. Regression analysis revealed that surface stiffness decreases linearly with increased gravimetric moisture content (p = 0.04). Traction was found to initially increase and then decrease with gravimetric moisture content. It was observed that: a surface of low moisture content provides low stud penetration and therefore reduced traction; a surface of high moisture content provides high stud penetration but also reduced traction due to a lubricating effect; and surfaces with moisture content in between the two extremes provide increased traction. In this study a standard commercially available stud was used and other studs may provide slightly different results. The results provide insight into the traction mechanisms at the stud-surface interface which are described in the paper. The variation between traction measurements shows the influence gravimetric moisture content will have on player performance. This highlights the requirement to understand surface conditions prior to making comparative shoe-surface traction studies and the importance of using a studded outsole that is appropriate to the surface condition during play.

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One, two, three or four: Does the number of Clegg hammer drops alter ground hardness readings on natural grass?

Twomey

Ullah

Petrass

2013

Proceedings of the Institution of Mechanical Engineers, Part P:

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The Clegg hammer is currently used to measure hardness of natural turf surfaces to inform performance and safety decisions. However, the number of Clegg hammer drops reported in natural grass testing varies from one to four drops, and the impact of the choice of the number of drops is unknown. The aim of this article is to determine whether significant differences exist between the four Clegg hammer drops on natural grass across a variety of conditions. Hardness readings (using a 2.25 kg Clegg hammer), soil moisture and botanical composition were recorded at nine different sites on seven football fields during an 18-week playing season. A total of 1255 hardness readings were collected for each of four consecutive Clegg hammer drops. Overall, there were significant differences between drop 1 and the other three consecutive drops, on all fields and on all sites. Deep soil moisture was the only factor that significantly influenced the hardness readings. The results of this study demonstrate that the decision regarding the number of drops recorded needs careful consideration as conclusions drawn on playability of a ground or the association with injury risk may vary considerably depending on the number of drops.

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Flow fields and losses downstream of an ultra-highly loaded turbine cascade with bowed blades

Cited by 4 publications

References 28 publications

The compound bowing design in a highly loaded linear cascade with large turning angle

The compound bowing design in a highly loaded linear cascade with large turning angle

The influence of gravimetric moisture content on studded shoe–surface interactions in soccer

One, two, three or four: Does the number of Clegg hammer drops alter ground hardness readings on natural grass?

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