This article attempts to propose a mathematical model and potential explanation regarding the unavoidable impact of a rigid body's peculiar shape on the seamless flow over it. The solid body completely immersed in a Newtonian fluid and respectively has a relative open circuit flow on it will typically experience various observable phenomena. These typical phenomena in laminar flow are explained using the proposed theory rather than conventional approximations or several partial theories. This article respectively represents an understanding of the laminar flow over a rigid body's external surface with due respect to its distinctive shape and size. To formulate a more realistic and simplified mathematical model for open circuit laminar flow over a body, a mathematical model is proposed based on the historical data of aerodynamics and theoretical mechanics. This mathematical model is intended to properly estimate forces on the continuous surface of the body in a laminar flow, to properly explain, understand and predict various phenomena like flow separation, flow transition, down-wash, stalling at the higher angle of attack, stalling velocity and how cambered airfoil can typically generate lift at a zero incidence angle. Most of all a mathematical model and the mechanism of streamline formation in an open-circuit laminar with respect to the shape and size of the body are illustrated.