Title: Dam break wave of a non-Newtonian thixotropic fluid

Description: The video shows the sudden release of a thixotropic fluid down a steep slope [1,2,3]. The practical applications range from debris flows on mountain slopes to the slump testing of self-flowing concretes as well as the ketchup sauce.

The video illustrates the effect of the fluid rest period on the flow motion. A well-mixed bentonite suspension does flow rapidly down the 15-degree slope. With increasing rest time, the thixotropic fluid properties change and the flow motion stops down the slope. For very long rest periods, the bentonite suspension behaves like a solid [4] and no fow motion is observed.

Thixotropy is the characteristic of a fluid to form a gelled structure over time when it is not subjected to shearing, and to liquefy when agitated. Thixotropic fluids are commonly used in the construction industry e.g., liquid concrete and drilling fluids, and related applications include some forms of mud flows and debris flows. This video describes a basic experimental study of dam break wave with some thixotropic fluid (bentonite suspensions) down a 15 degree channel [1,2,3].

After a brief introduction, the video presents 4 tests. The last 3 tests illustrate the effects of the rest time on the fluid propagation down the slope.

The work was conducted at the Laboratory of Materials and Structures in Civil Engineering LMSGC (France.) [3].

Credits: Hubert Chanson

References: [1] CHANSON, H., JARNY, S., and COUSSOT, P. (2006). "Dam Break Wave of Thixotropic Fluid." Journal of Hydraulic Engrg., ASCE, Vol. 132, No. 3, pp. 280-293 (ISSN 0733-9429). {http://espace.library.uq.edu.au/view/UQ:78856}

[2] CHANSON, H. JARNY, S., TOCQUER, L., and COUSSOT, P. (2004). "An Experimental Study of Sudden Release of Bentonite Suspensions down an Inclined Chute." Proc. 15th Australasian Fluid Mech. Conf., AFMC, Sydney, Australia, M. BEHNIA, W. LIN & G.D. McBAIN Ed., Paper AFMC00252, 4 pages (CD-ROM) (ISBN 1-864-87695-6). {http://espace.library.uq.edu.au/view/UQ:9429}

[3] CHANSON, H., COUSSOT, P., JARNY, S., and TOQUER, L. (2004). "A Study of Dam Break Wave of Thixotropic Fluid: Bentonite Surges down an Inclined Plane." Report No. CH54/04, Dept. of Civil Engineering, The University of Queensland, Brisbane, Australia, June, 90 pages (ISBN 1864997710). {http://espace.library.uq.edu.au/view.php?pid=UQ:9437}

[4] COUSSOT, P., ROUSSEL, N., JARNY, S., and CHANSON, H. (2005). "Continuous or Catastrophic Solid-Liquid Transition in Jammed Systems." Physics of Fluids, Vol. 17, No. 1, Article 011703, 4 pages (ISSN 0031-9171). {http://espace.library.uq.edu.au/view.php?pid=UQ:9444}

Web Page: http://espace.library.uq.edu.au/view/UQ:78856

Contributed By: Hubert Chanson