Scholarlink

<p>The flow velocity in metre-scale natural fracture networks readily exceeds centimetres per second, the threshold for non-stationary flow. However, despite widespread evidence of such dynamics, these are rarely considered in subsurface engineering applications, where steady-state simulation approaches dominate. Here, we compare Reynolds-averaged Navier-Stokes (RANS) and Detached-Eddy Simulation (DES) methods for the transient Navier-Stokes equation applied to fracture flow. These models are validated with experimental data of flow through fracture intersections. DES is then applied to a metre-scale fracture pattern with hundreds of discrete fractures, examining flow dynamics at velocities up to metres per second (m/s). DES accurately captures the temporal flow fluctuation and multiscale eddy formation, especially when a fine computational mesh is used in wake regions. By contrast, unsteady RANS fails to capture flow-field variations and produces results similar to steady RANS. DES reveals significant network flow periodicity (<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10596_2025_10361_Article_IEq1.gif" Format="GIF" Height="6" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">\(\sim \)</EquationSource> <EquationSource Format="MATHML"><math> <mo>∼</mo> </math></EquationSource> </InlineEquation>40 Hz) at m/s velocities, unlike the low-frequency results (<InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10596_2025_10361_Article_IEq1.gif" Format="GIF" Height="6" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">\(\sim \)</EquationSource> <EquationSource Format="MATHML"><math> <mo>∼</mo> </math></EquationSource> </InlineEquation>0.4 Hz) from RANS. We also explore the impact of unsteady flow on particle transport by integrating mixture-multiphase and rheological models into DES. Corresponding results indicate that inertia alters the concentration of transported solids, mixture viscosity, and particle dynamics such as clustering.</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 fluid dynamics on flow and transport in natural fracture networks

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年4月28日

查看全文
  • Cuong Mai Bui,
  • Stephan K. Matthai

摘要

The flow velocity in metre-scale natural fracture networks readily exceeds centimetres per second, the threshold for non-stationary flow. However, despite widespread evidence of such dynamics, these are rarely considered in subsurface engineering applications, where steady-state simulation approaches dominate. Here, we compare Reynolds-averaged Navier-Stokes (RANS) and Detached-Eddy Simulation (DES) methods for the transient Navier-Stokes equation applied to fracture flow. These models are validated with experimental data of flow through fracture intersections. DES is then applied to a metre-scale fracture pattern with hundreds of discrete fractures, examining flow dynamics at velocities up to metres per second (m/s). DES accurately captures the temporal flow fluctuation and multiscale eddy formation, especially when a fine computational mesh is used in wake regions. By contrast, unsteady RANS fails to capture flow-field variations and produces results similar to steady RANS. DES reveals significant network flow periodicity ( \(\sim \) ∼ 40 Hz) at m/s velocities, unlike the low-frequency results ( \(\sim \) ∼ 0.4 Hz) from RANS. We also explore the impact of unsteady flow on particle transport by integrating mixture-multiphase and rheological models into DES. Corresponding results indicate that inertia alters the concentration of transported solids, mixture viscosity, and particle dynamics such as clustering.