However, as the stream enters a bend and vortex flow commences as the primary flow, a secondary flow also commences and flows partly across the floor of the stream toward the convex bank ( the bank with the smaller radius ).
42.
Angle of attack is an important parameter for designing the artificial roughness . It has been found experimentally by many researchers that inclined ribs resulted in higher heat transfer rate than the transverse ribs due to the secondary flow induced in case of inclined ribs.
43.
The secondary flow is toward the center of the tornado or dust devil, and is then drawn upward by the significantly lower pressure several thousands of feet above the surface in the case of a tornado, or several hundred feet in the case of a dust devil.
44.
On the floor of the river bed the secondary flow sweeps sand, silt and gravel across the river and deposits the solids near the convex bank, in similar fashion to sugar or tea leaves being swept toward the center of a bowl or cup as described above.
45.
The nature of these instabilities is that of an exchange of stabilities ( rather than an overstability ), and the result is not turbulence but rather a stable secondary flow pattern that emerges in which large toroidal vortices form in flow, stacked one on top of the other.
46.
:: : The way a " slow rotation of the bulk liquid " is concentrated into an anomalous activity near the center of the bottom of the glass ( and other " weird behaviour of liquids in cups and glasses " ) may be the secondary flow of the boundary layer on the floor of the glass.
47.
A secondary flow of answering questions was more similar to traditional bulletin-board style interactions : a user sent a message to Aardvark or visited the " Answering " tab of the website, Aardvark showed the user a recent question from the user's network which had not yet been answered and which was related to the user's profile topics.
