Pipe flow

About: Pipe flow is a research topic. Over the lifetime, 13826 publications have been published within this topic receiving 351605 citations.

Developing Laminar Flow in a Pipe of Circular Cross-Section

Abstract: A method is described of predicting flow development and pressure drop in the inlet of a uniform pipe of circular cross-section for the incompressible isothermal laminar flow of a Newtonian fluid. Employment of both the differential and integral momentum equations leads to greater simplicity of expression than is found in other theoretical treatments, though the solutions obtained compare equally favourably with the limited experimental measurements available; those reported herein suggest the need for a more generalized analytical approach which covers non-isothermal flow and the effect on flow development of temperature-dependent viscosity.

Studies of the wall shear stress in a turbulent pulsating pipe flow

Abstract: : Measurements are presented of the time variation of the wall shear stress caused by the imposition of a sinusoidal oscillation on a turbulent pipe flow. The amplitude of the oscillation is small enough that a linear response is obtained and the dimensionless frequency, omega +, is large compared to that studied by most previous investigators. The most striking feature of the results is a relaxation effect, similar to what has been observed for flow over a wavy surface, whereby the phase angle characterizing the temporal variation of the wall shear stress undergoes a sharp change over a rather narrow range of omega +. At omega + larger than the median frequency of the turbulence there appears to be an interaction between the imposed flow oscillation and the turbulence fluctuations in the viscous sublayer, which is not described by present theories of turbulence.

Direct numerical simulation of a 30R long turbulent pipe flow at Reτ = 3008

Abstract: A direct numerical simulation of a turbulent pipe flow at a high Reynolds number of Reτ = 3008 over a long axial domain length (30R) was performed. The streamwise mean velocity followed the power law in the overlap region (y+ = 90–300; y/R = 0.03–0.1) based on the power law indicator function. The scale separation of the Reynolds shear stresses into two components of small- and large-scale motions (LSMs) revealed that the LSMs in the outer region played an important role in constructing the constant-stress layer and the mean velocity. In the pre-multiplied energy spectra of the streamwise velocity fluctuations, the bimodal distribution was observed at both short and long wavelengths. The kx−1 region associated with the attached eddies appeared in λx/R = 2–5 and λx/y = 18–160 at y+ = 90–300, where the power law was established in the same region. The kz−1 region also appeared in λz/R = 0.3–0.6 at y+ = 3 and 150. Linear growth of small-scale energy to large-scale energy induced the kx−1 region at high Reyno...

Fully resolved measurements of turbulent boundary layer flows up to

Abstract: Fully resolved measurements of turbulent boundary layers are reported for the Reynolds number range . Despite several decades of research in wall-bounded turbulence there is still controversy over the behaviour of streamwise turbulence intensities near the wall, especially at high Reynolds numbers. Much of it stems from the uncertainty in measurement due to finite spatial resolution. Conventional hot-wire anemometry is limited for high Reynolds number measurements due to limited spatial resolution issues that cause attenuation in the streamwise turbulence intensity profile near the wall. To address this issue we use the nano-scale thermal anemometry probe (NSTAP), developed at Princeton University to conduct velocity measurements in the high Reynolds number boundary layer facility at the University of Melbourne. The NSTAP has a sensing length almost one order of magnitude smaller than conventional hot-wires. This enables us to acquire fully resolved velocity measurements of turbulent boundary layers up to . Results show that in the near-wall region, the viscous-scaled streamwise turbulence intensity grows with in the Reynolds number range of the experiments. A second outer peak in the streamwise turbulence intensity is also shown to emerge at the highest Reynolds numbers. Moreover, the energy spectra in the near-wall region show excellent inner scaling over the small to moderate wavelength range, followed by a large-scale influence that increases with Reynolds number. Outer scaling in the outer region is found to collapse the energy spectra over high wavelengths across various Reynolds numbers.