Laboratory Study of Angular Momentum Transport in Sheared Rotating Flows

Other

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

Scientific paper

Rapid angular momentum transport in accretion disks is a longstanding astrophysical puzzle. Transport by molecular viscosity is inadequate to explain observationally inferred accretion rates. Since Keplerian flows are linearly stable in hydrodynamics, there exist only two main viable mechanisms for the required turbulence: nonlinear hydrodynamic instability or linear magnetorotational instability (MRI). The latter is regarded as a dominant mechanism for rapid angular momentum transport in hot accretion disks ranging from quasars and X-ray binaries to cataclysmic variables. The former is proposed mainly for cooler protoplanetary disks, whose Reynolds numbers are typically large. Despite their popularity, however, there is limited experimental evidence for either mechanism. In this talk, I will describe a laboratory experiment at Princeton (http://mri.pppl.gov) in a short Taylor-Couette flow geometry intended to study these mechanisms. Based on the results from prototype experiments and simulations, the apparatus contains novel features for better controls of the boundary-driven secondary flows. The experiments in water have shown1 that nonmagnetic quasi-Keplerian flows at Reynolds numbers as large as 2× 106 are essentially laminar, through means of direct measurements of Reynolds stress via a synchronized, dual Laser Doppler Velocimetry. Scaled to accretion disks, rates of angular momentum transport lie far below astrophysical requirements. By ruling out hydrodynamic turbulence, our results indirectly support MRI as the likely cause of turbulence even in cool disks. The experiments in liquid gallium eutectic alloy have recently begun, and initial results on MRI as well as other related phenomena including numerical predictions will be also discussed if available.
1. H. Ji, M. Burin, E. Schartman, & J. Goodman, Nature 444, 343-346 (2006).

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Laboratory Study of Angular Momentum Transport in Sheared Rotating Flows does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Laboratory Study of Angular Momentum Transport in Sheared Rotating Flows, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Laboratory Study of Angular Momentum Transport in Sheared Rotating Flows will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-1394334

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.