The ratio pA/p∞ is often used to express the local pressure at a specific point (pA) relative to the freestream pressure (p∞). Static Pressure in the Freestream (p∞): This represents the static pressure of the fluid in the undisturbed, free-flowing airstream far away from any object or disturbance. In aerodynamics, the freestream static pressure is often used as a reference point for measuring pressure changes caused by the presence of an object (e.g., an aircraft). It is denoted as “p∞” and is typically assumed to be a constant value when analyzing aerodynamic flows under certain conditions. Static Pressure at Point A (pA): This refers to the static pressure of the fluid at a specific location, denoted as “pA,” such as a point on an airfoil’s surface. The static pressure at point A is not necessarily the same as the freestream static pressure, as it can be affected by the shape of the object and the local flow conditions around that point. The value of pA helps characterize the local aerodynamic conditions and the pressure distribution on the object’s surface.
- Ratio of static pressure at point A to the total pressure (pA/p0)
- Ratio of static pressure at freestream to the total pressure (p∞/p0)
- Ratio of static pressures in the point A to the freestream (pA/p∞)