在潮通道中使用三种水音机流量屏蔽的性能
Emma Cotter1, James McVey1, Linnea Weicht1
1Coastal Sciences Division, Pacific Northwest National Laboratory, Sequim, Washington 98382, USAemma.cotter@pnnl.gov, james.mcvey@pnnl.gov, linnea.weicht@pnnl.gov, joseph.haxel@pnnl.gov.
JASA express letters
|January 10, 2024
概括
流屏有效减少水下流动噪声,这可以掩盖重要的声音. 一个装有油气的外提供了最好的降噪,而不会影响20kHz以上的声音信号.
科学领域:
- 声学 声学 在声学方面
- 流体动力学 流体动力学
- 海洋学 海洋学 海洋学
背景情况:
- 动荡的流体流产生伪音 (流动噪声),干扰声学测量.
- 流动噪声可以掩盖或扭曲水下重要的声音信号,影响声学监测和研究.
- 液电话流量屏蔽的设计旨在通过改变传感器周围的压力波动来最大限度地降低流量噪声.
研究的目的:
- 为了评估不同水音机流量屏蔽在减少流量噪声方面的有效性.
- 评估这些屏蔽对传播声信号减弱的影响.
- 为了确定在潮环境中用于水下声学应用的最佳流量屏设计.
主要方法:
- 测试了三种类型的水电话流量屏蔽:两种尼龙织物设计和一个装满油的外.
- 在潮通道中进行了实验,最大电流速度为1.3m/s.
- 测量流动噪声水平和声信号的减弱在各种频率.
主要成果:
- 所有经过测试的流量屏蔽都成功地减少了流量噪声.
- 没有任何一个屏蔽会对20kHz以上的传播声信号造成显著的衰减.
- 装满油的外表现出卓越的性能,在频率低于40 Hz的频率下,减少了超过30 dB的流动噪声.
结论:
- 液电话流量屏蔽是减轻水下声学调查中流量噪声的有效工具.
- 装满油的外提供了最显著的流量噪声降低,特别是在低频段.
- 这些发现支持使用适当的流量屏蔽来提高水下声学数据的质量.
相关概念视频
Rapidly Varying Flow
63
Rapidly varying flow (RVF) in open channels is characterized by abrupt changes in flow depth over a short distance, with the rate of depth change relative to distance often approaching unity. These flows are inherently complex due to their transient and multi-dimensional nature, making exact analysis difficult. However, approximate solutions using simplified models provide valuable insights into their behavior.Key Features of Rapidly Varying FlowRVF is commonly observed in scenarios involving...
63
Weir: Problem Solving
51
Water flow in open channels is often measured using hydraulic structures such as weirs, which allow precise calculation of discharge. In a rectangular channel, flow rates are measured using three types of weirs: rectangular sharp-crested, triangular sharp-crested, and broad-crested. The weir head is set at a fixed height above the channel bottom, simplifying calculations and enabling the relationship between depth and flow rate to be analyzed.For the rectangular sharp-crested weir, the flow...
51
Hydraulic Jump: Problem Solving
61
To analyze a hydraulic jump in a rectangular channel with a flow speed of 6 meters per second, follow these steps:Calculate Effective Upstream Velocity:When the downstream gate closes, a hydraulic jump forms, traveling upstream at 2 meters per second. This wave speed combines with the initial channel flow velocity, creating an effective upstream velocity.Identify Flow Velocities Before and After the Hydraulic Jump:Upstream of the hydraulic jump, the effective flow velocity includes both the...
61
Typical Model Studies
359
Fluid mechanics model studies often utilize scaled-down systems to predict fluid behavior in full-scale environments, such as river flows, dam spillways, and structures interacting with open surfaces. Maintaining Froude number similarity in river models is crucial, as it replicates surface flow features like wave patterns and velocities.
359
Uniform Depth Channel Flow
74
Uniform depth channel flow keeps fluid depth consistent along channels such as irrigation canals. In natural channels, such as rivers, approximate uniform flow is often assumed. This condition occurs when the channel’s bottom slope matches the energy slope, balancing potential energy lost from gravity with head loss due to shear stress. This balance prevents depth changes along the channel length, resulting in a steady, uniform flow.Uniform flow in open channels with a constant cross-section...
74
Uniform Depth Channel Flow: Problem Solving
66
To calculate the flow rate for a trapezoidal channel, first, identify the bottom width, side slope, and flow depth of the channel. The cross-sectional area (A) corresponding to the depth of flow (y), channel bottom width (B), and side slope (θ) is determined by:Next, calculate the wetted perimeter, which includes the bottom width and the sloped side lengths in contact with the water. Using the values of the cross-sectional area and the wetted perimeter, determine the hydraulic radius by...
66


