Pipe flow with large particles and their impact on the transition to turbulence

• The classical transition from laminar to turbulent flow is affected if solid particles are added. The transition behavior is a function of particle size d and solid volume fraction phi and the flow undergoes a smooth transition, as opposed to intermittent, if phi exceeds a certain threshold. In this work we show that, for particle-laden pipe flows with large particle-to-pipe diameter ratios d/D, the phi threshold for altering the transition is much lower than previously reported for smaller particles. Magnetic resonance velocimetry reveals that particles introduce turbulent-like fluid velocity fluctuations in laminar flow. Factors that might control the limits between "classical" and "smooth" transition in the state space spanned by d/D and phi are discussed based on scaling analyses.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Strömningsmekanik och akustik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Fluid Mechanics and Acoustics (hsv//eng)

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)