Purpose

This paper aims to present the jet mixing effectiveness of triangular tabs with semi-circular corrugations to control the subsonic and sonic correctly expanded jets.

Design/methodology/approach

Three semi-circular corrugated triangular tabs (Tab A, Tab B and Tab C) of equal blockage 5.11% are used, in which the corrugation locations on the tabs are varied. The offset distance between the semi-circular corrugations at the leaned edges of the triangular tabs are 0.0, 0.75 and 1.5 mm for the Tabs A, B and C, respectively. Two identical semi-circular corrugated tabs has been placed exactly 180° apart at the exit of the convergent nozzle. The pitot pressure measurements were taken to study the jet mixing characteristics of the tabs for the jet exit Mach numbers of 0.6, 0.8 and 1.0, and it is compared with the free jet.

Findings

The jet centerline pitot pressure decay reveals that, Tab A is very effective than Tab B and Tab C. For the jet exit Mach numbers of 0.6, 0.8 and 1.0, the potential core reduction for the Tab A is found to be 69.1%, 69.7% and 70.8%, respectively, when compared with the free jet.

Practical implications

The semi-circular corrugated triangular tabs were found to be more effective than the plain triangular tabs of equal blockage ratio for reducing the core length with minimum thrust loss.

Originality/value

The offset distance of the semi-circular corrugations are varied along the leaned sides of the triangular tabs, which is the novelty of this study.

中文翻译：

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半圆形波纹片控制亚音速和正确扩展的音速射流

目的

本文旨在展示具有半圆形波纹的三角形片的射流混合效果，以控制亚音速和音速正确扩展的射流。

设计/方法/方法

三个半圆形波纹三角形凸片（Tab A、Tab B和Tab C）采用等堵5.11%，凸片上的波纹位置不同。三角形接片倾斜边缘的半圆形波纹之间的偏移距离对于接片 A、B 和 C 分别为 0.0、0.75 和 1.5 毫米。两个相同的半圆形波纹片在收敛喷嘴的出口处正好相隔 180°。进行皮托管压力测量以研究射流出口马赫数为 0.6、0.8 和 1.0 时翼片的射流混合特性，并将其与自由射流进行比较。

发现

射流中心线皮托管压力衰减表明，Tab A 比 Tab B 和 Tab C 非常有效。对于 0.6、0.8 和 1.0 的射流出口马赫数，发现 Tab A 的潜在核心减少量为 69.1%、69.7与自由射流相比，分别为 % 和 70.8%。

实际影响

半圆形波纹三角翼片被发现比同等堵塞比的平面三角形翼片更有效，以减少芯部长度和最小推力损失。

原创性/价值

半圆形波纹的偏移距离沿着三角形凸片的倾斜边变化，这是本研究的新颖之处。