This work is devoted to the study of the stability of Hagen–Poiseuille flow or pipe flow. The analysis is focused on the streak breakdown process by which two-dimensional streamwise-independent finite amplitude perturbations transiently modulate the basic flow leading to a profile that contains saddle points and is linearly unstable with respect to very small streamwise-dependent perturbations....

The failure pressure of pipe with wall-thinning was investigated by using three-dimensional elastic-plastic finite element analyses (FEA). With careful modeling of the pipe and flaw geometry in addition to a proper stress-strain relation of the material, FEA could estimate the precise burst pressure obtained by the tests. FEA was conducted by assuming three kinds of materials: line pipe steel, ...

The response of pipe flow to physically realistic, temporally and spatially continuous (periodic) forcing is investigated by decomposing the resolvent into orthogonal forcing and response pairs ranked according to their contribution to the resolvent 2-norm. Modelling the non-linear terms normally neglected by linearisation as unstructured forcing permits qualitative extrapolation of the resolve...

Different flow patterns of downward gas-liquid two-phaseflow using simple mixer are studied in an experimental manner. An experimental setup is designed and fabricated to allow the visual observation of downward two-phase flow patterns and their transitions. The flow patterns are recorded by a 1200 frames per second high speed video camera. The quality of downward two-phase flow patterns photos...

It has been well established that heat transfer in a helical coil is higher than that in a corresponding straight pipe. However, the detailed characteristics of fluid flow and heat transfer inside helical coil is not available from the present literature. This paper brings out clearly the variation of local Nusselt number along the length and circumference at the wall of a helical pipe. Movemen...

Both cavitation erosion and liquid impingement erosion are phenomena that can cause pipe wall thinning in power plants. The Code for Power Generation Facilities, Rules on Pipe Wall Thinning Management, was published by the JSME (Japan Society of Mechanical Engineers) in 2005. The code says that cavitation erosion shall be prevented either in the design stage or by daily inspection. On the other...

in this study, using sound created by wheat grain passing through a pipe, wheat flow rate was measured. the developed device consists of a hopper, metering device, sound sensor, delivery tube, dc motor and power supply. several wheat mass flow rates were tested and the sound signal created by the passage of the grain through the discharge tube was measured and transferred to a computer using da...

Recent numerical studies suggest that in pipe and related shear flows, the region of phase space separating laminar from turbulent motion is organized by a chaotic attractor, called an edge state, which mediates the transition process. We here confirm the existence of the edge state in laboratory experiments. We observe that it governs the dynamics during the decay of turbulence underlining its...

Pipe flow is perhaps the classic problem of fluid dynamics. Its simplicity of form lends itself admirably to experimenters but conceals a wealth of unanswered questions. Despite Reynolds’ conducting his seminal experiments over a century ago, few formal results are known for this flow. Over the years many simplifications have been considered, including linearisation, azimuthal invariance and st...

Leo H. O. Hellström, a) Bharathram Ganapathisubramani, b) and Alexander J. Smits c) Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, U.S.A. Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, U.K. Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, U.S.A., and Mechanical and Aerospace Engineer...