Maritime transport

Maritime transport (or ocean transport) or more generally waterborne transport, is the transport of people (passengers) or goods (cargo) via waterways. Freight transport by sea has been widely used throughout recorded history. The advent of aviation has diminished the importance of sea travel for passengers, though it is still popular for short trips and pleasure cruises. Transport by water is cheaper than transport by air or ground, but significantly slower for longer distances. Maritime transport accounts for roughly 80% of international trade, according to UNCTAD in 2020. Maritime transport can be realized over any distance by boat, ship, sailboat or barge, over oceans and lakes, through canals or along rivers. Shipping may be for commerce, recreation, or military purposes. While extensive inland shipping is less critical today, the major waterways of the world including many canals are still very important and are integral parts of worldwide economies. Particularly, especially any material can be moved by water; however, water transport becomes impractical when material delivery is time-critical such as various types of perishable produce. Still, water transport is highly cost effective with regular schedulable cargoes, such as trans-oceanic shipping of consumer products – and especially for heavy loads or bulk cargos, such as coal, coke, ores, or grains. Arguably, the industrial revolution had its first impacts where cheap water transport by canal, navigations, or shipping by all types of watercraft on natural waterways supported cost-effective bulk transport. Containerization revolutionized maritime transport starting in the 1970s. "General cargo" includes goods packaged in boxes, cases, pallets, and barrels. When a cargo is carried in more than one mode, it is intermodal or co-modal. A nation's shipping fleet (variously called merchant navy, merchant marine, or merchant fleet) consists of the ships operated by civilian crews to transport passengers or cargo from one place to another.

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Related exercises (7)

The siphon

We use the siphon of the figure to empty a container of water. At the exit of the tube, the shrinking factor is 0.6. i) What is the water velocity at the exit of the tube? ii) What is the maximal height of the siphon if we want to avoid the formation of bubbles (cavitation) at the top of the siphon? The vapor pressure of water is P_(sat)u2004=u20041765 Pa. The edge of the siphon is located 2m under the bottom of the container. The flow is sufficiently weak so that we can consider the height of fluid constan

Free surface of a vortex

Consider the vortex formed by an ideal fluid which flows by a hole at the bottom of a container. The potential of velocities for this flow is, with a correct approximation :

\Phi(\theta)=\frac{\Gamma}{2\pi}\,\theta ~,

where Γ is a constant. Check that the flow is irrotational. Then use the Bernoulli law to determine the shape of the free surface of the vortex. Considering the symmetry of the problem, we will use the cylindrical coordinates (r,θ,z). For the given potential the velocity field is:

Rotating disks

Two disks A and B of radius R, aligned, can rotate around a vertical axis z inside a container filled with a fluid of viscosity η. The distances between A and B and between A and the bottom of the container are equal to d. The disk B rotates at constant angular velocity ω₀xa0e⃗_(z). At tu2004=u20040 the angular velocity of A is ωu2004=u20040.

What is the moment of viscous forces applied on A at tu2004=u20040xa0?
What is the sum of the moments acting on A when the velocity is ω ? (N.B.: A has two sur

The rower

A rower goes up a river at constant velocity. He pulls a bottle of wine attached by a rope to his boat. When he goes under a bridge, the bottle is detached and goes down the river. The rower realises it one hour later. He makes a U-turn and recovers his bottle 1 kilometer down the river from the bridge. What is the velocity of the river relatively to the shore? The problem is in one dimension. We consider the referential of the Earth (absolute) linked to a coordinate system Ox, where O is a point of the sho

Trip to Mars

A spaceship is launched from Earth to Mars. We want its trajectory’s perihelion to correspond to the Earth’s position when it launched, and the aphelion to correspond to Mars’ position when it arrives (see diagram). We consider Earth and Mars to be on circular coplanar orbitals with R_(E)u2004=u20041u2005 AU and R_(M)u2004=u20041.52u2005 AU (1 AU = 1 astronomical unit = average distance from Sun to Earth= 149.6u2005×u200510⁹xa0m). The Earth’s revolution period T_(E) lasts one year. We don’t know the spacesh