Scholarlink

<p>Turbulent flow over rough walls are of great interest in engineering and geophysical applications, since real-world boundaries are rarely smooth. This paper investigates the influence of transitioning surface roughness heights and varying particle densities of roughness features on turbulent flow patterns. This study investigates the flow patterns measured with an Acoustic Doppler Velocimeter and confirms that, at each measurement station, the classical log law provides a reasonable representation of the experimental streamwise velocity profiles in the inner flow region, consistent with established findings for rough-bed open-channel flows. Turbulent quantities such as Reynolds stresses and turbulent kinetic energy are estimated using the variance method. Results indicate that as roughness height increases, near-wall turbulence intensifies, leading to thicker boundary layers, greater momentum loss near the bed, and increased flow resistance. Conversely, sediment particle density influences sediment stability and packing, which can indirectly affect near-bed flow structures and local turbulence intensities. This study presents a combined experimental and numerical investigation of turbulent flow over rough surfaces. The systematic analysis of a range of roughness heights, from fine to coarse bed conditions, under different discharge conditions, together with a quantitative validation of Computational Fluid Dynamics predictions against ADV-based experimental measurements using percentage deviation is done. The CFD model reproduces the overall shape and magnitude of the experimental velocity profiles with RMSE values of 0.031–0.061&#xa0;m/s and R<sup>2</sup> exceeding 0.80 in eight of ten cases in the region above z = 0.002&#xa0;m. This study helps improve the design of surfaces used in areas like water flow systems, air flow systems, and machines that transfer heat in industries.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Influence of roughness height and sand particle density on turbulence patterns in open channel flow surfaces

  • 期刊论文

  • 发表日期：

    2026年8月4日

查看全文
  • Kirti Singh,
  • Kesheo Prasad

摘要

Turbulent flow over rough walls are of great interest in engineering and geophysical applications, since real-world boundaries are rarely smooth. This paper investigates the influence of transitioning surface roughness heights and varying particle densities of roughness features on turbulent flow patterns. This study investigates the flow patterns measured with an Acoustic Doppler Velocimeter and confirms that, at each measurement station, the classical log law provides a reasonable representation of the experimental streamwise velocity profiles in the inner flow region, consistent with established findings for rough-bed open-channel flows. Turbulent quantities such as Reynolds stresses and turbulent kinetic energy are estimated using the variance method. Results indicate that as roughness height increases, near-wall turbulence intensifies, leading to thicker boundary layers, greater momentum loss near the bed, and increased flow resistance. Conversely, sediment particle density influences sediment stability and packing, which can indirectly affect near-bed flow structures and local turbulence intensities. This study presents a combined experimental and numerical investigation of turbulent flow over rough surfaces. The systematic analysis of a range of roughness heights, from fine to coarse bed conditions, under different discharge conditions, together with a quantitative validation of Computational Fluid Dynamics predictions against ADV-based experimental measurements using percentage deviation is done. The CFD model reproduces the overall shape and magnitude of the experimental velocity profiles with RMSE values of 0.031–0.061 m/s and R2 exceeding 0.80 in eight of ten cases in the region above z = 0.002 m. This study helps improve the design of surfaces used in areas like water flow systems, air flow systems, and machines that transfer heat in industries.