An oil tanker is moving on the water surface in a sea with...

An oil tanker is moving on the water surface in a sea with the velocity of $2.5 \mathrm{~m} / \mathrm{s}$. The oil tanker has a smooth surface area of $5.4\left(10^{3}\right) \mathrm{m}^{2}$ in contact with the sea. Determine the friction drag on its hull and the power required to overcome this force. Take $\rho=1030 \mathrm{~kg} / \mathrm{m}^{3}$ and $\mu=1.14\left(10^{-3}\right)$ $\mathrm{N} \cdot \mathrm{s} / \mathrm{m}^{2}$

Key Concepts

Friction Drag

Friction drag is the force exerted by a fluid flowing over a body, resulting from the viscous shear stress on the body’s surface. It depends on the fluid’s properties (such as viscosity and density), the velocity of the flow, and the area of the surface in contact with the fluid. This concept is crucial in understanding how drag forces oppose the movement of objects in a fluid.

Reynolds Number

The Reynolds number is a dimensionless quantity used to predict flow patterns and determine whether a flow will be laminar or turbulent. It characterizes the relative importance of inertial forces versus viscous forces in the flow and is key in choosing appropriate correlations for calculating friction coefficients in problems involving fluid motion over surfaces.

Friction Drag Coefficient

The friction drag coefficient, or skin friction coefficient, is a dimensionless parameter that quantifies the contribution of viscous shear to the drag experienced by an object. It is typically derived from empirical correlations that depend on the Reynolds number, and it is used to calculate the shear stress on the surface which, when integrated over the wetted area, gives the friction drag force.

Power Requirement Against Drag

The power required to overcome drag is the rate at which work must be done to maintain motion against the resistive friction drag force. It is calculated as the product of the drag force and the velocity of the moving body. This concept is important for estimating the energy efficiency and propulsion requirements in engineering systems involving fluid flow.

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