Exams › GATE › Technical

Consider incompressible laminar flow of a constant property Newtonian fluid in an isothermal circular tube. The flow is steady with fully-developed temperature and velocity profiles. The Nusselt number for this flow depends on

1. neither the Reynolds number nor the Prandtl number
2. both the Reynolds and Prandtl numbers
3. the Reynolds number but not the Prandtl number
4. the Prandtl number but not the Reynolds number

Correct answer: neither the Reynolds number nor the Prandtl number

Solution

In fully-developed laminar flow in a circular tube, the Nusselt number is constant and determined solely by the geometry and flow conditions, not by the Reynolds or Prandtl numbers, which influence heat transfer in other flow regimes.

Related GATE Technical questions

• Assuming constant temperature condition and air to be an ideal gas, the variation in atmospheric pressure with height calculated from fluid statics is
• A hollow cylinder has length L, inner radius r1, outer radius r2, and thermal conductivity k. The thermal resistance of the cylinder for radial conduction is
• Consider the radiation heat exchange inside an annulus between two very long concentric cylinders. The radius of the outer cylinder is Ro and that of the inner cylinder is Ri. The radiation view factor of the outer cylinder onto itself is
• The internal energy of an ideal gas is a function of
• In the phase diagram shown in the figure, four samples of the same composition are heated to temperatures marked by a, b, c and d. At which temperature will a sample get solutionized the fastest?
• The welding process which uses a blanket of fusible granular flux is

⚔️ Practice GATE Technical free + battle 1v1 →