Drag force flat plate

Glycerin at 30°C flows past a 30-cm-square flat plate at a velocity of 1.5 m/s. The drag force is measured as 8.9 N (both sides of the plate). Calculate the heat-transfer coefficient for such a flow system. 

G. Laminar and turbulent, flat plate, forced flow >=7h = = 0.037 Chilton-Colbum analogies, Nsc = 1-0, (gases), /= drag coefficient. Corresponds to item 5-21-F and refers to same conditions. 8000 < < 300,000. Can apply analogy,=/ 2, to entire plate (including laminar portion) if average values are used. [100] p. 193 [109] p. 112 [146] p. 201 [151] p.271... 

We utilize the physics of rolling particles on a surface as developed by Bhattacharya and Mittal. Our treatment differs from that of Bhattacharya and Mittal in that we provide a more detailed description of the turbulent boundary layer which is formed in the steady state when a fluid flows over a flat plate.The drag force we use is consistent with the treatment of Gim et al. ... 

A 2-m X 3-m flat plate is suspended in a room, and is subjected to air flow parallel to its surfaces along its 3-m-long side. The free stream temperature and velocity of air are 20°C and 7 m/s. The total drag force acting on the plate is measured to be 0.86 N. Determine the average convection heal transfer coefficient for the plate (Fig. 5-36). 

SOLUTION A flat plate is subjected to air flov/, and the drag force acting on it is measured. The average convection coefficient is to be determined. Assumptions I Steady operating conditions exist. 2 The edge effects are negligible. 3 The local atmospheric pressure is 1 atm. 

For flat plates, the drag force is equivalent to friction force. The average friction coefficient Qcan be determined from Eq. 6-11,... 

C What does the friction coefficient represent in flow over a flat plate How is it related to the drag force acting on the plate ... 

Drag force acting on a flat plate normal to the flow depends on tlie pressure only, ind is independent of the wall shear, which acts normal lo the free-stream flow. 

For parallel flow over a flat plate, the pressure drag is zero, and thus the drag coefficient is equal to the friction coefficient and the drag force is equal to the friction force. 

Engine oil at 60°C flows over the upper surface of a 5-m long flat plate whose temperature is 20°C with a velocity of 2 m/s (Fig. 7-12). Determine the total drag force and the rate of heat transfer per unit width of the entire plate. 

Noting that the pressure drag is zero and thus Cp = C, (or parallel ffov/ over a flat plate, the drag force acting on the plate per unit width becomes... 

Engine oil at 80°C flows over a 10-m-long flat plate who.se temperature is 30 C with a velocity of 2.5 m/s. Determine Ihe total drag force and the rate of heal iransfer over Ihe entire plate per unit width. 

A thin, square flat plate has 0.5 ra on each side. Air at J0°C flows over the top and bottom surfaces of the plate in a direction parallel to one edge, with a velocity of 60 m/s. The surface of the plate is maintained at a constant temperature of 54 C. The plate is mounted on a scale that measures a drag force of 1.5 N. 

Consider laminar flow of a fluid over a flat plate maintained at a constant temperature. Now the free-slreani velocity of the fluid is doubled. Determine the change in the drag force on the plate and rate of heat transfer between the fluid and tlie plate. Assume the flow to remain laminar. 

Rngine oil at 105 C flows over the surface of a flat plate who.se temperature is 15°C with a velocity of 1.5 m/s. The local drag force per unit surface area 0.8 m from the leading edge of the plate is... 

The formula for the viscosity coefficient of a gas can be derived in a way similar to that used f or heat conduction. We imagine two very large parallel flat plates, one lying in the xy-plane, the other at a distance Z above the xy-plane. We keep the lower plate stationary and pull the upper plate in the + x direction with a velocity U. The viscosity of the gas exerts a drag on the moving plate. To keep the plate in uniform motion, a force must be applied to balance the viscous drag. Looking at the situation in another way, if the upper plate moves with a velocity U, the viscous force will tend to set the lower plate in motion. A f orce must be applied to the lower plate to keep it in place. 

In Sec. 6.13 we showed that the drag force on numerous bodies could be represented in terms of plot of drag coefficient versus Reynolds number. If we now define a local drag coefficient for some small part of a flat plate as... 

Consider a flat plate such as a single blade on an agitator, with a fluid passing about it at a relative velocity, v. The dynamic pressure exerted on the plate is theoretically and the theoretical force F is this pressure multiplied by the plate area, i.e. f, = pv A. The actual force on the plate F is related to the theoretical force by a drag coefficient Co where Co = FJF thus ... 

They offered expressions for the drag coefficient versus the gas Reynolds number for each of the three aspect ratios (see chapter 5 for details). For e < 0.25, the ellipse becomes thin and close to a plate shape and one can assume a value of Cd 2, which is a reasonable value for a flat plate over a wide range of Reynolds numbers. So, as the element is being deformed by the aerodynamic force in our model, its instantaneous Reynolds number (based on its semi-major axis) and the corresponding drag coefficient can be calculated by interpolating between the expressions offered for drag by Mashayek et al. [6]. As shown by their study. 

A polymer solution (density 1022 kg/m ) flows over the surface of a flat plate at a free stream velocity of 2.25 m/s. Estimate the laminar boundary layer thickness and surface shear stress at a point 300 mm downstream from tlie leading edge of the plate. Determine the total drag force on the plate from the leading edge to this point. What is the effect of doubling the free stream velocity ... 

In Fig. 3.1-la the flow of fluid is parallel to the smooth surface of the flat, solid plate, and the force F in newtons on an element of area dA m of the plate is the wall shear stress T times the area dA or x dA. The total force is the sum of the integrals of these quantities evaluated over the entire area of the plate. Here the transfer of momentum to the surface results in a tangential stress or skin drag on the surface. 

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