Convection

Consider incompressible laminar flow over a flat plate with freestream velocity of $u_{\infty}$. The Nusselt number corresponding to this flow velocity is $Nu_1$. If the freestream velocity is doubled, the Nusselt number...

Consider a hydrodynamically fully developed laminar flow through a circular pipe with the flow along the axis (i.e., z direction). In the following statements, $T$ is the temperature of the fluid, $T_w$ is the wall tempe...

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 depe...

Which of the following non-dimensional terms is an estimate of Nusselt number?

In the following two-dimensional momentum equation for natural convection over a surface immersed in a quiescent fluid at temperature T ∞ (g is the gravitational acceleration, β is the volumetric thermal expansion coeffi...

Consider a hydrodynamically and thermally fully-developed, steady fluid flow of 1 kg/s in a uniformly heated pipe with diameter of 0.1 m and length of 40 m. A constant heat flux of magnitude 15000 W/m 2 is imposed on the...

A fluid (Prandtl number, $$Pr=1$$) at $$500$$ $$K$$ flows over a flat plate of $$1.5$$ $$m$$ length, maintained at $$300$$ $$K.$$ The velocity of the fluid is $$10\,\,m/s.$$ Assuming kinematic viscosity, $$v = 30 \times...

Grashof number signifies the ratio of

For flow of viscous fluid over a flat plate, if the fluid temperature is the same as the plate temperature, the thermal boundary layer is

The ratio of momentum diffusivity $$\left( \upsilon \right)$$ to thermal diffusivity $$\left( \alpha \right),$$ is called

For flow through a pipe of radius $$R,$$ the velocity and temperature distribution are as follows: $$U\left( {r,x} \right) = {C_1}$$ and $$T\left( {r,x} \right) = {C_2}\left[ {1 - {{\left( {{r \over R}} \right)}^3}} \rig...

In the laminar flow of air $$(Pr=0.7)$$ over a heated plate, if $$\delta $$ and $${\delta _T}$$ denote, respectively the hydrodynamic and thermal boundary layer thickness, then

For laminar forced convection over a flat plate, if the free stream velocity increases by a factor of $$2,$$ the average heat transfer coefficient

Match Group $$A$$ with Group $$B$$ Group-A $$P:$$$$\,\,\,\,\,\,\,$$ Biot number $$Q:$$$$\,\,\,\,\,\,\,$$ Grashof number $$R:$$$$\,\,\,\,\,\,\,$$ Prandtl number $$S:$$$$\,\,\,\,\,\,\,$$ Reynolds number Group-B $$1:$$$$\,\...

Water flows through a tube of diameter $$25mm$$ at an average velocity of $$1.0m/s.$$ The properties of water are $$\rho = 1000\,\,kg/{m^3},$$ $$\mu = 7.25 \times {10^{ - 4}}\,\,N.s/{m^2},$$ $$\,K = 0.625W/m.K,$$ $$Pr=4....

The non-dimensional fluid temperature profile near the surface of a convectively cooled flat plate is given by $${{{T_w} - T} \over {{T_w} - {T_\infty }}} = a + b{y \over L} + c{\left( {{y \over L}} \right)^2},$$ where $...

Water (specific heat, $${c_p} = 4.18\,\,kJ/kgK$$ ) enters a pipe at a rate of $$0.01$$ $$kg/s$$ and temperature of $${20^ \circ }C.$$ The pipe, of diameter $$50$$ $$mm$$ and length $$3$$ $$m,$$ is subjected to a wall hea...

Water (specific heat, $${c_p} = 4.18\,\,kJ/kgK$$ ) enters a pipe at a rate of $$0.01$$ $$kg/s$$ and temperature of $${20^ \circ }C.$$ The pipe, of diameter $$50$$ $$mm$$ and length $$3$$ $$m,$$ is subjected to a wall hea...

The ratios of the laminar hydrodynamic boundary layer thickness to thermal boundary layer thickness of flows of two fluids $$P$$ and $$Q$$ on a flat plate are $${1 \over 2}$$ and $$2$$ respectively. The Reynolds number b...

Match the following List-$${\rm I}$$ $$P.$$ Compressible flow $$Q.$$ Free surface flow $$R.$$ Boundary layer flow $$S.$$ Pipe flow $$T.$$ Heat convection List-$${\rm II}$$ $$U.$$ Renolds number $$V.$$ Nussult number $$W....

A coolant fluid at $${30^ \circ }C$$ flows over a heated flat plate maintained at a constant temperature of $${100^ \circ }C$$. The boundary layer temp distribution at a given location on the plate may be approximated as...

For flow of fluid over a heated plate, the following fluid properties are known: Viscosity $$=0.001Pa.s;$$ Specific heat at constant pressure $$=1$$ $$kJ/kgK;$$ Thermal conductivity $$=$$ $$W/mK,$$ The hydrodynamic bound...

The temp distribution within the Laminar thermal boundary layer over a heated isothermal flat plate is given by $$\left( {T - {T_w}} \right)/\left( {{T_\infty } - {T_w}} \right) = \left( {3/2} \right)\,\,\left( {y/{\delt...

An un-insulated air conditioning duct of rectangular cross section $$1\,\,m \times 0.5\,m,$$ carrying air at $${20^ \circ }C$$ with a velocity of $$10 m/s,$$ is exposed to an ambient of $${30^ \circ }C$$. Neglect the eff...

An un-insulated air conditioning duct of rectangular cross section $$1\,\,m \times 0.5\,m,$$ carrying air at $${20^ \circ }C$$ with a velocity of $$10 m/s,$$ is exposed to an ambient of $${30^ \circ }C$$. Neglect the eff...

Consider a laminar boundary layer over a heated flat plate. The free stream velocity is $${U_\infty }.$$ At some distance $$x$$ from the leading edge the velocity boundary layer thickness is $${\delta _v}$$ and the therm...

The properties of mercury at $$300K$$ are : density $$ = 13529kg/{m^3},$$ $${C_P} = 0.1393$$ $$kJ/kgK,$$ dynimic viscosity $$ = 0.1523\,\, \times \,\,{10^{ - 2}}\,\,N - s/{m^2}$$ and thermal conductivity $$=8.540$$ $$W/m...

Water (Prandtl number $$=6$$ ) flows over a flat plate which is heated over the entire length. Which one of the following relationship between the hydrodynamic boundary layer thickness $$\left( \delta \right)$$ and therm...

Hot water flows with a velocity of $$0.1$$ $$m/s$$ in a $$100mm$$ long, $$0.1m$$ diameter pipe. Heat lost from the pipe outer wall is uniform and equal to $$420$$ $$W/{m^2}$$. If the inlet water temperature is $${80^ \ci...

Heat transfer coefficients for free convection in gasses, forced convection in gases and vapors, and for boiling water lie, respectively, in the range of

Match List - $${\rm I}$$ with List - $${\rm II}$$ and select the correct answer using the code given below the Lists: List - $${\rm I}$$ $$A.$$ Grashof number $$B.$$ Schmid number $$C.$$ Weber number $$D.$$ Fourier numbe...

For air near atmospheric condition flowing over a flat plate the laminar thermal boundary layer is thicker than hydrodynamic boundary layer

A fluid flowing over a flat plate has the following properties: dynamic viscocity $$ = 25 \times {10^{ - 6}}\,\,kg/ms,$$ specific heat $$=2.0 $$ $$kJ/kgK,$$ thermal conductivity $$0.05W/mK.$$ The hydrodynamic boundary la...

In pool boiling the highest $$HTC$$ occurs in

For the fluid flowing over a flat plate with Prandtle number greater than unity, the thermal boundary layer for laminar forced convection