Q1: For what value of Prandtl number, St = f/2?

ANS:B - 1

In fluid mechanics, the Stanton number (St) is defined as the ratio of convective heat transfer to conductive heat transfer. St=kh​ Where:

• ℎh is the convective heat transfer coefficient,
• k is the thermal conductivity.

The Stanton number is often related to the Nusselt number (Nu) and the Prandtl number (Pr) through empirical correlations. One such correlation for forced convection heat transfer is: St=Re⋅PrNu​ Where:

• Re is the Reynolds number.

Given that 2St=2f​, where f is a function dependent on the flow regime and geometry, and knowing that St=Re⋅PrNu​, we can rearrange the equation to solve for Pr: Pr=Re⋅StNu​ Therefore, for 2St=2f​, the Prandtl number must satisfy: ⋅(2)Pr=Re⋅(2f​)Nu​ The exact relationship between Pr and St depends on the specific flow conditions and geometry, and it cannot be determined directly without additional information. However, we can say that for 2St=2f​, Pr would be greater than 1, as the Stanton number is typically defined for convective heat transfer situations where >1Nu>1, and in such cases, the Prandtl number is generally greater than 1.