... theoretical, experimental, and field data studies of the effects of drillpipe rotation on annular frictional pressure loss for laminar, helical flow of power law fluids. With drillpipe dynamic influence, the annular pressure loss is the combined result of shear-thinning effect and drillpipe dynamic effect...

... in the circulation system are precisely known. One of the major challenges in determining actual annular pressure losses is that the non-Newtonian fluid flow in annular conduit is much more complex than pipe flow. Many investigators proposed different equivalent diameter concepts to link annular flow to well defined...