Question #660585 on Yade changed: https://answers.launchpad.net/yade/+question/660585
Robert Caulk posted a new comment: OK, my testing leads me to believe that the deformations are not large enough in a hydraulic fracture simulation to change the Delaunay triangulation. Therefore, it should be safe to update positions the normal way. I've found that the remesh interval needs to be much smaller than if we do not update the particle positions (1/5th-ish). So I guess simulation speed was the only real issue, but the slow down is not due to setting positions, but instead due to the more frequent remesh requirement (and frequent solver building associated with it). In comparison, the hydraulic fracture behavior difference is pronounced for fixed particle positions vs updated positions. For updated positions, the rate of injection pressure drop is about half of the rate observed for fixed particle positions. Further, the crack area is greater for the fixed positions by 5-10% compared to the updated positions. So the fracture is propagating faster at lower injection pressures for the fixed positions, and the fracture is propagating slower at higher injection pressures with updated positions. This makes sense, considering we aren't considering the impact of the changing void volume on pressures for the fractured cells when we fix positions. When we update positions, these void volumes increase in fractured cells, the pressures decrease slightly due to fluid compressibility, and the pore pressure at the tip will not be as high, leading to lower fluid induced forces and a slower propagation of the fracture. For fixed positions, a fractured cells void volume remains the same for the duration of the simulation. So as soon as the fluid pressure increases in a fractured cell, the pressure raises more quickly and the fluid induced forces follow, leading to quicker fracturing, and the fluid moves more quickly to the next cell. For updated positions, the fracture is propagating slower, the pressure is not relieved as quickly by the fast permeability changes enabled by fractured cells. In other words, the slow process of opening the fracture is accommodated when we update positions, whereas fixed particle positions yield stiffer and less accommodating fracture propagation behavior. -- You received this question notification because your team yade-users is an answer contact for Yade. _______________________________________________ Mailing list: https://launchpad.net/~yade-users Post to : [email protected] Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
