As the airflow over the upper surface increases, static pressure and dynamic pressure change how?

As the airflow over the upper surface increases, static pressure and dynamic pressure change how?

• A. Static decreases, dynamic increases
• B. Static increases, dynamic decreases
• C. Static decreases, dynamic decreases
• D. Static increases, dynamic increases

Answer: (C)

As the local airflow over the upper surface speeds up, the air there has more kinetic energy, so the dynamic pressure increases. Bernoulli’s principle for steady, incompressible flow says the sum of static and dynamic pressure is roughly constant along a streamline. Since dynamic pressure rises with speed (q = 1/2 ρV²), the static pressure must fall where the velocity increases. So the upper surface experiences a decrease in static pressure while the dynamic pressure increases as the flow accelerates. This contrast—lower static pressure and higher dynamic pressure on the fast-moving upper surface—helps explain why the top surface has lower pressure and contributes to lift.

As the local airflow over the upper surface speeds up, the air there has more kinetic energy, so the dynamic pressure increases. Bernoulli’s principle for steady, incompressible flow says the sum of static and dynamic pressure is roughly constant along a streamline. Since dynamic pressure rises with speed (q = 1/2 ρV²), the static pressure must fall where the velocity increases. So the upper surface experiences a decrease in static pressure while the dynamic pressure increases as the flow accelerates. This contrast—lower static pressure and higher dynamic pressure on the fast-moving upper surface—helps explain why the top surface has lower pressure and contributes to lift.