بررسي مفهوم سطح ويژه ي سنگ دانه ها در تحليل غيرخطي جريان در محيط هاي متخلخل دانه يي

STUDYING THE SPECIFIC SURFACE CONCEPT FOR NON LINEAR FLOW THROUGH COARSE GRANULAR POROUS MEDIA

Though various relationships for the non-linear analysis of flow through coarse porous media may be found in the literature, their applicability for engineering usage is limited. Difficulties in determining the grain mean hydraulic radius is a basic issue in this regard, due to the complexities in estimating the specific surface pa¬rameter involved for such calculations. After reviewing related theoretical bases, this article examines the relia¬bility of a number of recent models proposed for deter¬mination of the specific surface, using actual data. Find¬ings indicate that the Sabin-Hansen method is a more realistic means for such a purpose and, in spite of itʹs simplicity, the Bazargan model leads to least accurate results.