Tank Baffle Plate

Any baffle is put to break the stream line flow there by agitating the fluid, It also increases the effective surface area.

Both these effect increases the heat exchange effectiveness,

One use of a baffle is to prevent any form of vortexing to appear when the agitator is activated.

.....and thereby increase the effectiveness of the agitation as compared to an unbaffled tank of the same geometry and configuration of agitator.

Baffle plates are used in some semi trailer and straight truck tanker applications to preserve vehicle stability when accelerating or braking. The plate somewhat (depending on design) prevents sloshing of the product while in transit.