Search results
Results from the WOW.Com Content Network
H s is the design significant wave height at the toe of the structure (m) Δ is the dimensionless relative buoyant density of rock, i.e. (ρ r / ρ w - 1) = around 1.58 for granite in sea water; ρ r and ρ w are the densities of rock and (sea)water (kg/m 3) D n50 is the nominal median diameter of armor blocks = (W 50 /ρ r) 1/3 (m)
At a basic level, it is typically calculated in metres using the formula: [1] UKC = Charted Depth − Draft-/+ Height of Tide. Ship masters and deck officers can obtain the depth of water from Electronic navigational charts. [5] More dynamic or advanced calculations include safety margins for manoeuvring effects and squat. [7]
A vessel's length at the waterline (abbreviated to L.W.L) [1] is the length of a ship or boat at the level where it sits in the water (the waterline). The LWL will be shorter than the length of the boat overall (length overall or LOA) as most boats have bows and stern protrusions that make the LOA greater than the LWL. As a ship becomes more ...
During uniform flow, the flow depth is known as normal depth (yn). This depth is analogous to the terminal velocity of an object in free fall, where gravity and frictional forces are in balance (Moglen, 2013). [3] Typically, this depth is calculated using the Manning formula. Gradually varied flow occurs when the change in flow depth per change ...
Hull speed can be calculated by the following formula: where is the length of the waterline in feet, and is the hull speed of the vessel in knots. If the length of waterline is given in metres and desired hull speed in knots, the coefficient is 2.43 kn·m −½.
The use of the depth–slope product — in computing the bed shear-stress — specifically refers to two assumptions that are widely applicable to natural river channels: that the angle of the channel from horizontal is small enough that it can be approximated as the slope by the small-angle formula, and that the channel is much wider than it is deep, and sidewall effects can be ignored.
Before choosing a formula it is worth knowing that in the paper on the Moody chart, Moody stated the accuracy is about ±5% for smooth pipes and ±10% for rough pipes. If more than one formula is applicable in the flow regime under consideration, the choice of formula may be influenced by one or more of the following:
From this equilibrium the wave setup can be calculated. The maximum increase in water level is then: = where H b is the wave height at the breaker line and γ is the breaker index (wave height/water depth ratio at breaking for individual waves, usually γ = 0.7 - 0.8). Incidentally, due to this phenomenon, a small reduction in water level ...