1. The seventh wave theory and its computational principles in nature often reveal a wide range of fluctuations in the water surface, which is often referred to as wave movements. Waves are one of the most common phenomena in the oceans. They are the most important drivers and forces of the evolution of the beaches, seaports and naval projects. The causes of ocean fluctuations are many, such as wind, atmospheric pressure changes, gravity of celestial bodies, low density of different layers of the ocean and earthquakes on the sea floor. Most waves are driven by the wind, and those who customarily call them "winds" or "waves" o-waves depend on the speed of the wind, its timing and the size of the wind zone. So far, 34 m of the worst wind waves have been observed on the sea surface. The waves cause fatigue in the structure of the oceans, and they also impact on the safety of ships' navigation and anchorage. The power of the waves also tends to cause underwater mud movement near the shallow waters, causing the beach to collapse, and before the building, there was brushing, port ii and flight
2. Sedimentation occurs and water depth is reduced, affecting ship navigation and berthing. For the safety of marine structures, pilot ships and ship terminals, there must be some understanding of wave theory. When the wind subsides or when the wind moves outside the wind zone, the water surface continues to fluctuate as a result of inertia and gravity, and the wave moves at this time are free waves, known as “surges” or “spills”. In deep water, surges can take a portion of the energy lost as a result of frictions within the water body and frictions between the surface and the air, the main energy being consumed by bottom-to-floor stifling after entry into the shallow water zone, and by fragmentation. In order to study the characteristics of the wave, it is necessary to classify the resulting wave or wave in transmission. In general, the balance of the water surface has become unbalanced by external interference, but the effect of surface tension, gravity, etc. Has brought the imbalance to balance, but due to inertia, the balance has always been
3. It is difficult to achieve, and thus the free surface of the water body is subject to cyclical and regular fluctuations, while the water point of the volatile part is characterized by a cyclical resonance of the wave. Waves can be classified according to external interference. Wind-induced waves call them wind waves. Waves caused by gravity from the sun, the moon and other celestial bodies are called tidal waves. Waves caused by underwater earthquakes are called seismic waves caused by ship navigation. The most significant of these impacts on the security of the maritime structure are wind waves. Wind waves fluctuate on the surface of water, also known as surface waves. The wind is an external factor for volatility, and the internal factor for volatility is gravity. Thus, in terms of stress, wind waves are called gravity waves. There are different types of waves, depending on the form of the wave and the movement. They can be high or low and can be short-lived. Waves can be static one-on-one waves, or moving one
Four, one boost wave (a wave that spreads in one direction at a certain speed) can be either a single wave or a wave of series of waves. §7-1 fluid basic equations must follow certain rules, which are the basic equations of fluid movement. To facilitate the study of fluctuations in seawater, it is assumed that seawater is an ideal fluid. The ideal fluid is to look at it as a continuous medium that is absolutely non-compressable, non-inflatable, non-glazing, non-surface tension and vapour pressure (the latter two for liquids). For ideal fluids, the motion equation can be: du 1dpdt p dxdv 1dpdt p dy 1 dpg (7-1) dt dz:u > w is the weight of water points velocity in the direction of the three axis x, y, z; p is the density of seawater
5; p is the surface strength of the fluid; g is the acceleration of gravity. When describing the flow field in oraf, the sports equation is: dududu1 dpl+vl+wl =-dx6dzp dxdv i+vdvd>fwl = 1 dpdx*dzpydvdwdwl1 dprf v +w=dx6dzp dz-8du+u dtdv+ "dtdw+u dtt2. Continuous equation flows must follow the constant law of quality, i. E. Must meet the continuous equation. (7-2) takes a fixed geometric space today in the flow consisting of a closed-curvature s-iwi, the size of which is intended. The increase in the mass of the internal fluid taken in the unit time is as follows: the net flow of fluid mass into the space through the boundary at the same time is as follows: type s: the dagger indicates the speed of the fluid mass point along the extra-legal line of the boundary
6. Scale. According to the constant law of quality: (7-3) kawasaka+preserve=° for ideal fluids, there are: =0 consecutive equations of ideal fluids in general form because of their arbitrary size: (74) + h = udx dy dz iii, boundary condition 1 and benthic kinetic boundary conditions cannot cross the seabed boundary, but can only move along the line of the boundary, i. E. =0 (7-5) (7-9) formula: you are the speed of the water point along the line of law; the speed of movement of zero seawater; and d the distance from the sea surface. When fluids are motionless, their velocity and velocity are related to dx60w=2 and the sporting boundary conditions (7-6) (7-7) (7-8) z = x, y, t) of the free surface: (a wave function of a free surface. 3. Movement of free surface (sea surface)
7. Mechanical boundary condition p=po1 if =g & =. In form: po is sea surface pressure. § 7-2 microwave theory i, velocities and wave-sided equations are easy to analyse, taking into account two-dimensional fluctuations, and the continuous equation becomes: du dv viiidx dz because it contains generic non-linear items in formula (7-2)" (° %j, etc.) for small £ = amplitude/wavelength, which is to be solved by an aerodynamic method. Sets the following extensions: u = + s2u2 + (7-10) w = + sw2 + (7-11) and: "g = (column + +. 仏) = dane + 0 (thirty in the above formula, item). O(f) could be omitted at the outset. For 2d fluctuations, the formula (7-1) is (7-12) (7-13)du 1
8, dpdt p dxdt p dz (7-14), however, it is not clear whether motion is or is not spinning, generally considered to be spinning and introduction of flow functions, = 0 = 0 = gaping (7j3) and (7-14) after elimination (7-15) (7-16) incubation (7-15) and (7-17) incubation (7-17) due to bloodworker 0, so/ (2) £2 = 0. On the contrary, if shao dynasty were to be included in this relationship, the movement expressed above the animal + %0 (7-18) would be non-stop. Thus, a zero-speed approach can be introduced at the beginning, i. E. 11 = 収, w: empty + empty = 0dx2 dv, if the above-form approach is appropriate, then the top-form solution could be the same as shaw's, and read: (7-19) 0 = heart” (7-20) set (7-27) z
9 = c宀c can be derived from: 0 = ic coshk(d + + above the actual text, 0 = ccoshr(d + z) sin (also i cot) is available from free surface kinetic boundary conditions (7-21) = -coshkdcos (kx-cot) g for slight fluctuations: = acokx-cot) contrast (7-22) and (7-23), available (7-22) (7-23) a = coshkdg) (7-24)
10. An important wave parameter formula is sought below wave characteristics parameters. On the free surface, command: f(x,z,z)=-77(x,r)=o = o received above: df 丄f °f °3 = 0dt dt x dz (7 - 24) (7 - 25) (7 - 25) or (7 - 29) wear +0 = 0 (= “) = 0 (`), + £ 0, + + = 0; = > + + + + + 82 j2 + upper form only determines the £ rank, the successor (7 - 27), removes the items containing the second tier and above, and is available: e. G. Plastic, “0 dt & general, omitted, mark 1, available: one formula, z = odt dz by 7 - 25) and mode (by 7 - 25)
11, 7-29), available: co2 = gktankd (7-28) (7-29) (7-30) formula referred to as dispersive equation, because bit phase velocity (or wave velocity) c = %, so available: c =, b tanhkd = jtanh-(7-31) v kv 2/r2: if the geometrical basis of the stun-03 geometrical decision is based on the fact that the wave's surface is tilted at the same or human value, the wave breaks. Different wave breaking indicators can be derived from different geometric parameters, and geometrical jurisprudence can therefore be expressed in various ways. Mccowan analyzes the vertical axis at the extreme tip of the wave
The symmetrical maximum wave shape, with a maximum wave angle limit of 120 being proposed. And then the waves come to a broken conclusion. 2. Michell provides a limit for the ratio of wave height to wavelength at the limit steep value, which is broken when exceeded. Deepwater wave the expression of steepness is 8=h (lmichell's limit of 0. 142) when it comes to deepwater 5 and beyond this value breaks. The expression of the shallow wave steepness is: d = h / (ltanhkd) michele's limit for shallow water was still 0. 142o michel and michele's belief that, whether deep or shallow, when the wave height and wavelength ratio equal 0. 142, the wave would break. But many scholars think that their conclusions are merely theoretical values that are not in line with reality, and that the threshold of 5 obtained through experiments is more realistic than 0. 12. 3 - extreme
The concept of relative wave height extremes, such as wave heights, breaks when the limit of wave height to water depth is given, reaching or exceeding that limit. The experience formula given by yamada is:'-1. 5-(l+15tan4, shh/l0=a l-e": hb is a break-off wave height with a deep-water wavelength and depth when a wave is broken. For the angle of the seafloor slope, a is the coefficient and a ii 0. 17o can be seen from the top pattern: the relative wave height of the limit varies with the angle of the slope. But different scholars have come up with different results, some of which are classic: 0. 73, 0. 78, 0. 83 and 1. 03, all of which are based on motor science judgments in even water depths. 4 the limit wave slope value longuet-higgins presents the extreme wave slope values by analysing the characteristics of the breakup of the deep water wave. According to lo
>30. 37° = 0. 586dx as the time series of wave surfaces measured at fixed points are used in practice, it is not possible to use the results directly. To do that, you have to convert. As: x = ct the pre-style can be rewritten as: |沪86 if: r(t) = 殂, c = 0. 58 (the geometry of the broken xspell wave is: dtr» j § 7-8 random wave theory considers the wave as a random process, introduces the concept of the spectrum and studies the wave on this basis, has formed the central issue of current wave research. With random waves, applySpectrum analysisThe analysis of the platform's structure in terms of power will need to be based on the ocean
43. The requirements of the works and the circumstances of the area in which they are located, and the selection or production of the appropriate wave spectrum. , basic concept 1, random waves are random due to changes in their speed and pressure relative to location and time. Waves are made up of waves of varying amplitudes, frequency, phase and random nature. Although the wave is t-volatile, any wave can be expressed in gill form: 00x"(/) = + for heart cos/76x + sin/7dxn-1; i-l is written in plural form: 007 (0= m strict/jx: generational (3) in form (2); it is: "dual earth is called strict transformation: 00??"; (/) = j(°) twilight-cc type: (/) and (0) swaps. 2. Water quality in random waves in random waves
The average total energy at point 44 is: £ = £ dco: ;) =lmi|z7()|2t->x /stt(co) is called the energy spectrum of a random wave, which is also called spectro-density or power spectral density because it is equal to the average total energy of a wave in the entire frequency area. Format: s(e) is the power spectral density of the wave surface: r3 is the self-relevant function of the wave surface. Ii. The production of the wave spectrum1 and the direct method are measured by the wave height time cycle “(f), which is evaluated by the relevant function r). Based on the definition of the relevant function: (/ + r)dt and then by shade, get ss. 2. The indirect method obtains the wave spectrum by obtaining a coefficient in the function based on the functional form of the existing wave spectrum through measured data. Iii. Several recognized waves have so far produced many waves, among them:
45, a significant portion of which is in newman's first form in 1952: 4s() = extcoIn the ' formula, the index is 5-6 and q is 24, and parameters a and b contain parameters such as wave elements (e. G. Wave height and cycle). The main advantages of this form are simple structure and ease of use. 1 on the upper right side; partly with reduced frequency, the high frequency part of the spectrum affects more people; the index function segment increases rapidly from 0 to 1 to zero in q = 0, so that the two parts are multiplied by a sharp increase in the beginning, as shown in figures 7-3, and then sharply reduces and gradually zero. The formula includes four volumes, p, q, a and b, which can be adjusted to give a more human space to reflect the effects of external factors on the spectrum. The main disadvantage of this spectrum is that the theory is inadequate, and to a great extent, it's an empirical formula, and secondly, it's high and non-existent
46. Obstacles to in-depth research. So far, the japanese graph 7-3 wave spectrum has been recognized in the world as affecting more people: pierson-moskowitz, 1964, issc, 1967, jo, 1968-1969The nswap spectrum, the bretsclmeider-mitsuyasu spectrum of 1970, the wallops spectra of 1987 and the anglican spectra of 1990 are all based on observations made in different areas of the world, differences between different waves and the forms of the spectrum directly affect power calculation, making it necessary to study the application of various typical waves in specific areas. The improved jonswap spectrum q) spectral density formula for k is (4-55) (1. 09-0. 0191 hn t>), 0. 062380. 23+o33q o. 185 (19 +u)-11 0. 13 2 (u + 0. 2) 7559 is referred to as the spectral peak cycle with a peak coefficient of 2 ghb equal to (7 = 0. 07, co cdpu is a spectra elevation factor with an observed value of 1. 5-6. 0, with an average of 3. 3. B-m spectrum density formulas are: (4-56), a = 0. 257/j/t, b = 1. 03/7',/3tp = 1. 057 ' . / o3, modified wallops spectrum density formula: s'g = 0 also called (op4 (q(4-57)) xz +
