Instabilities in vertically vibrated fluid-grain systems

Abstract

When a bed of fluid-immersed fine grains is exposed to vertical vibration a wealth of phenomena may be observed. At low frequencies a horizontal bed geometry is generally unstable and the bed breaks spatial symmetry, acquiring a tilt. At the same time it undergoes asymmetric granular convection. Fine binary mixtures may separate completely into layers or patterns of stripes. The separated regions may exhibit instabilities in which they undergo wave-like motion or exhibit quasi-periodic oscillations. We briefly review these and a number of related behaviours, identifying the physical mechanisms behind each. Finally, we discuss the magneto-vibratory separation of binary mixtures which results from exposing each component to a different effective gravity and describe the influence of a background fluid on this process.

Effect of friction on the granular U-tube instability

“…The U-tube instability has been addressed by several authors (Gutman, 1976;Rajchenbach, 1991;King et al, 2007;Clement et al, 2009;Sánchez et al, 2009). A similar instability has been studied in partitioned containers (see Fig.…”

“…2), by Ohtsuki et al (1998) and Akiyama et al (2001). Previous works have studied the effect of several parameters: Akiyama et al (2001) and Sánchez et al (2009) performed experiments under vacuum; King et al (2007) and Clement et al (2009) changed the interstitial fluid; Sánchez et al (2009) and Darias et al (2011) systematically varied the amplitude and frequency of vibration; Ohtsuki et al (1998) addressed the geometry of the tube and the wall friction. This last parameter plays a poorly understood role in the development of the instability.…”

Convection, Segregation and Pattern Formation in Horizontally Vibrated Granular Materials

“…The granular convection and segregation of binary or other systems in vertical shaking are extensively discoursed [14][15][16][17] and granular convection always remains significant for the segregation patterns [18][19][20][21][22][23][24] . Different convection patterns are observed due to heaping, [25,26] , tilting, [25,27] etc. in vertically vibrated systems.…”

“…Segregation in vertically vibrated granular systems also reveals extensive range of interesting phenomena [28][29][30][31][32][33][34][35][36] . A variety of segregation patterns [37][38][39][40][41][42][43][44][45][46][47] are also observed in vertically vibrated systems, such as stripe patterns [46] wave-like patterns [27] , BNE and RBNE [34,47] etc. Only limited studies explored the effects of horizontal direction vibration.…”

Air-grain interfaces in spinning granular films at high rotation rates

“…Vevrek and Baxter [4] found out that the surface shape of sand in the spinning bucket depends on the imposed rotational rate. They have used a dimensionless parameter which was defined as = ω (R/g) 1/2 , where R is the radius of the container, and g is the acceleration due to gravity.…”