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# Ocean Waves - Science topic

Explore the latest questions and answers in Ocean Waves, and find Ocean Waves experts.

Questions related to Ocean Waves

There are two different waves of the gravitational field (GF):

**1. Gravitational field transverse wave.**What it reflects is the disturbance of the surrounding GF, and the transmission speed of this disturbance is equal to the slow light speed c. For example, the motion of the sun disturbs the GF generated by the center of the galaxy, causing transverse waves of GF around the sun.

**2. Gravitational field longitudinal wave.**It is generated by the gravitational source itself, and GF will transfer energy quickly, and this speed is much greater than the speed of light c.

When the gravitational source changes (position, mass), this change will first be reflected on the longitudinal wave of GF, and distant objects will feel the change of GF soon. At the same time, the disturbance of the gravitational source to other surrounding GFs will propagate to the surroundings at a slow speed c in the form of transverse waves.

**To make an inappropriate analogy:**when you throw a stone into a calm lake, you will observe slow water waves spreading around, which is the disturbance of the stone to the water surface, thus generating water waves. But in addition to water waves, there are sound waves in the water. The speed of the sound waves is much faster than that of the water waves, and the sound waves in the water arrive long before the slow water waves reach the shore.

**A brief summary:**the longitudinal wave of GF is produced by the gravitational source itself, and the transverse wave of GF is produced by the disturbance of the gravitational source to other surrounding GFs.

**Newtonian gravity**studies "sound waves in water", the longitudinal waves of GF.

**Einstein GR**studies the "water wave", that is, the transverse wave of GF.

I hope that you can understand the whole gravity from my simple narrative. You can also download my two papers on gravity here:

Kind regards,

Tony

Can anybody suggest tool for simulation of water waves. Or how to do it in COMSOL?

hey,

I have data of waves taken nearby the coast , I would like to transform the wave data by reverse refracting to get an idea of the deep ocean waves. could anyone recommend a software or a technique to reverse refract wave data?

I need to simulate the movement of a moored buoy shell in the diameter of 20 cm with an internal ball (diameter in 3 cm) in the water wave, with the accuracy of engineering project.

I am familiar with Ansys Fluent and COMSOL. But I recently heard of more engineering software such as Ansys AWQA，and 3D Flow.

Thus, I need some recommendation and references on a suitable software. An explanation of the advantage and drawback on different software will be really appreciated.

The most celebrated equation which describes water waves is the Korteweg-deVries(KdV) equation. Some of the assumptions which go into this equation are incompressibility, irrotationality, inviscid, small amplitude and long wavelength. I want to throw the assumption of irrotationality out. Instead, I want to replace it with the actual vorticity equation in 2D which is Dw/Dt=0, where D/Dt is the material derivative and w=v_x-u_y.

Can I still do the same asymptotic reduction to get a weakly nonlinear equation for waves? If not, Why not?

Hi

What frequency specification should I use in order to create a low-pass filter (specifically filter order and Frequency specifications)? I have a huge data set which contains unfiltered water level data and it is in meters relative to mean lower water (MLW) at hourly intervals. The time stamp is in Julian data.

thank you in advance.

I am interested to perform spectral analysis of a structure under random waves. could anyone suggest me a book or an example that starts from wave spectrum (such as

**, P-M etc) to RAO. A complete example from formulation to numerical evaluation.**

*JONSWAP spectrum*I have been searching an open-source tsunami modelling code for calculating tsunami wave propagation using finite-fault model.

I looked into COMCOT (Cornell Multi-grid Coupled Tsunami Model) and found a couple of articles that has been done with using slip distribution models, but version 1.7 (that i can find on the internet) does not seem to be working properly.

So in summary i am looking for a code that does;

1.Nested grid with different grid size

2.Using slip distribution model for calculating initial wave and propagation

3.Plotting maximum wave height

4. Comparing the results with the observed tsunami data (tide-gauges or DART buoy records), tsunami wave heights versus time

Liquid will move more and having more amplitude in comparison to Earth

Rogue waves are an important topic in water waves, plasma physics, nonlinear optics, Bose Einstein condensate and so on

How can we predict a rogue wave?

Hi every one,

I have a series of ocean wave data such as wave height, period, direction and etc. I want to analysis the data and draw association diagram such as wave rose,frequency distribution and etc. What software is useful for this purpose?

Thanks a lot.

Hello Everyone.,

I am having confusion regarding to calculate wave breaker angle.

wave breaker angle was calculated as the difference between the peak wave direction and the direction normal to the depth contour.

I don't know how to find breaker angle in the right manner.

Thank you in advance, who helped me

Movement of submarines is expected to give disturbances in water.

Morning all,

My first post on Research Gate! Hopefully it helps my endeavor :] and warning, it is long!

As the title said, I am brainstorming topics for my thesis. I am enrolled as MS, but will pursue PhD afterwards.

I am extremely interested in WECs. I have worked on a solar-based project before, and, until enrolling at OSU, had never heard of water based renewable energies! I'm so enthralled by them that I am taking a graduate CE course to better understand water wave mechanics.

The problem is, while I am an EE, I am not 500% interested in, for example:

- PE: for WECs, this might be designing a circuit with a super capacitor to help smooth the power output

- Control strategies through simulation: e.g. MPC in Simulink/WECsim

I have feared that maybe I chose wrong, and a ME/CE would suit me better, but all my advisors have told me that, "EEs wear multiple hats, we will surely find something for you"

Now to find what that something is!

I said "not 500%" because, I

**DO**think those topics are interesting. I ask my friends hours on end what their PE circuit is, and to explain their method, and even go home and research to gain a fundamental understanding; I read a 50pg MPC document and covered each page top to bottom in notes you can't even tell where the original text is; I've attended WECSim courses to see how they are implementing control strategiesBUT it is not what I would want my thesis topic to be (I don't think, who knows maybe I start and I like it!)

I have talked to my advisor a lot, but am now reaching out to the power of the internet for various opinions...

**So, does anyone have any ideas on what could be researched?**

The only topic I found interesting when him and I were discussing were some WECs self adjusting to their environment.

Also, I know that most WECs are designed to work best at a certain frequency, but is there research out there regarding a WEC that could work at multiple frequencies, or change its' internal circuitry (control strategy) to better work at the average changing frequency of incoming waves?

Anything is really helpful. I am and will continue thoroughly researching and talking to many folks in the field to find something I am really passionate about, because in the end, that will make for a larger impact on the world.

Thanks,

- Chris

I am focusing on the 3D-1D reduction of the Water-Waves equations in an open channel. What conditions should I impose on the intersection of the free surface and the bathymetry. I'm demanding if the condition of non-penetration at the bottom is sufficient ? thanks for your answers.

There are many different forms of vortexes in the physical world. Here are two common examples:

**Tornado vortex**. These are common atmospheric disturbance in the Midwest in North America (see, e.g., the attached image).

**Seashell vortex**. Seashell sometimes are vortex-shaped (see, e.g., the attached image).

I am hoping that followers of this thread can post or point to other examples of vortexes in the physical world.

Here are several more examples more examples:

**Photon vortex and electromagnetic vortexes**.

This interest in vortexes is related to photon vortexes and electromagnetic vortexes.

**Shape Vortexes [Geometry and Algebraic Topology]**.

From a shape theory perspective, it seems that many physical shapes are non-concentric, nesting cycles. In homology theory, the analogue of a physical vortexes is a collection of non-concentric, nesting 1-cycles. A 1-cycle is a collection of connected edges or surfaces that form a connected path so that one can find a path between any pair of vertices in the 1-cycle.

Linear wave theory for inviscid fluids gives a shallow water wave speed of c = (gy)^0.5. Is there an approximate solution that applies to viscous fluids? I am particularly interested in non-Newtonian fluids (sediment-water slurries). Can anyone point to experimental work on viscous/non-Newtonian fluids? Thanks!

I am trying to simulate the gap resonance between two floating bodies and with a gap of 3m under the effects of ocean wave (direction longitudinal of the ships body) . I am trying to put surge, sway and yaw as fixed. There should be a damping effect on floating bodies due to viscous effect and radiation . How do I determine the linear and damping coefficient of such bodies. This is my first time simulating a multiphase flow and needed advice on this.

I have wave spectra time series and I use some partitioning and tracking algorithms to identify swell events and wind sea events. My aim is to model separately frequency time evolution in a swell event case and a wind sea event case.

- In case of swell event, since the swell celerity in deep water is g/(4pf), the frequency of waves generated at a single remote location and arriving at some observation point increases linearly with time. According to this, I choose an increasing linear model for pic frequency time evolution in a swell event.

- Now, what kind of model can I choose in wind sea event case? Actually I use a decreasing linear model assuming that the energy transferred by wind to sea water contribute to decrease the frequency. Is it a coherent hypothesis? Can you recommend another model to me?

I have compiled waveDyMFoam successfully (OpenFOAM 2.4.0).

But when I use the solver to simulate a free floating ship model in regular waves (only heave motion allowed), the velocity of the ship increases rapidly, making the running process crashed.

Has anyone solved the problem??

I am analysing a coastal time-series of hourly temperature and salinity measurements. I have calculated the density using Gibbs seawater toolbox (TEOS10). In addition I have also calculated the seawater density/stability ratio $R_{\rho}$,

$R_{\rho} = \frac{\alpha \Delta\Theta}{\beta \Delta S_A}$.

Specifically, I want to distinguish between density changes affected by either changes in temperature or salinity. So far I have just seen articles analysing the spatial distribution of the density/stability ratio, either vertical or horizontal, and mentioning that when $-1 < R_{\rho} < 1$, the density is affected mostly by changes in salinity.

Could anyone please suggest further references, especially analysing this ratio using time-series?

Cheers!

please help me. i have developed a model in simulink to model a power generation system from ocean waves. i have used a three phase asynchronous generator block along with the a three phase RLC load in series and a three phase RLC load in parallel. The parameters for the generator block is known from literature but parameters for the two RLC loads are not known. Please help me to put suitable values to them. and also help me to obtain the variation of power generated in the generator with time.

I want to simulate open-channel flow in ANSYS CFX with a cylinder inside the water, which has a distance from bottom and free surface. I want to simulate free surface waves due to the existence of cylinder. The inlet water is assumed to be laminar. I have done this project by using the method in tutorial 9 of ANSYS CFX but the result is not acceptable. As you can see in the picture, free surface waves appeared between cylinder and inlet, which should be appeared between cylinder and outlet. (Flow direction is from left to right.)

The drag coefficient increase with wind speed up to a limited value (~35m/s),the roughness reduces to virtually zero by ~80m/s wind speed. (Leo Holthuijsen's JGR paper 2012). An idealized condition, if hurricane wind speed bigger than 70m/s (category 5), the drag coefficient is very low (towards zero), how is the ocean waves? how does wind energy/momentum go to the ocean currents?

Do any one know how to find 'Directional spreading index, n' or

'Directional standard deviation, DSD' of Ocean waves?

Free SAR Wave Mode Data Download

Hi all,

I'm looking for references regarding the implementation of WW3 for the NE Atlantic by IFREMER. I have access to the hindcasts through the IFREMER ftp but I can't find any reference regarding the implementation. Can anyone help with this.

Thanks in advance!

I'm working on modelling the propagation and dissipation of waves in both the marginal ice zone and also in the ice pack. My understanding is that in the ice pack we may get both scattering (from changes in ice thickness as described in papers by Squire for example) and dissipation which may occur due to the viscosity in the water (this I know how to deal with) and also the creep effect in the ice. I've found the 1973 paper by Wadhams about this but I imagine that there may be more recent updates on the ice properties ... and that these properties may be different for steady or oscillating loads. I just started to read a few papers by Timco, but I am a bit lost.

So, basically I was going to use Wadhams' theory, with some updates on the mechanical properties of sea ice. Any advice is welcome.

What are the open source software for Tsunami modeling?

thanks and regards

sowmya

Lower resolution CTD can miss too much of the detail maybe?

I dont have any buoy data at the particular locations, anybody pls let me the suggetion

Charnock parameter is approximately saturated under high wind speeds.Will Charnock parameter be decreased under gale-force winds? What is the role of the wave age and sea spray on this possible decrease?

Hi

I try to use optimal interpolation and kalman filter method of data assimilation for water wave data with fortran and matlab. but before using these methods in wave modeling, I want to test my fortran and matlab codes with simple examples. so I tried to estimate a supposed simple quadratic equation with methods mentioned above but the results are Disappointing. could u plz give me a numerical example that helps me to learn these methods?

I have been working on synthetic aperture radar data for retrieving ocean wave spectra, and i was using python for the process i was successful only to the extent of reading raster data, i would like to know whether python has any module for sar data processing as further processing of SAR data is getting complex

I have been working on some SAR data Sets like RISAT-1 and RADARSAT-2 , I have extracted the pixel information using python and I would like to know how this information can be used to extract wave and wind information over open ocean

This is the definition everyone uses, including myself. But just because everyone uses does not justify that it is valid.

We are looking into time series of vertical buoy (Datawell) or radar displacement measurements of the ocean surface and are trying to discriminate between outliers and extreme waves. Has anybody got experience with this task?

Clearly freak waves happen all the time in the ocean, but only being noticed when someone nearby encounters it or becomes a victim of it because it happens unexpectedly.

The unexpectednes is a fact everyone recognizes, but no one can do much about it.

The main failure of the conventional definition of greater than twice significant wave height is simply its failure reflecting unexpectedness. Hence this question!

Nonlinear Schrodinger equation is a completely integrable Hamiltonian system. It admits infinite number of conserved quantities. It also admits rational solution (or rogue wave solution).The main character of this solution is unstable and it appears nowhere without a trace. So my question is what happen to the energy of the rogue wave when it goes off.

Why the usual(spilling wave) assumption of the wave height inside the surf zone being proportional to the water depth will conflict with the important matter of the distribution of the applied longshore stress across the surf zone?

statistical and spectral analysis of ocean waves

For a moored structure in waves, calculation of wave drift damping of the body is of vital importance for calculation of the slow drift motion. However, how to calculate the wave drift damping in a more concise way?

I normally work with the degrib dos command line which is practical to extract data from ECMWF as you can have many years and different variables in a single file, if you reduce the geographical location for which you are extracting the data. The problem is that I downloaded some wave data from NCEP, and for each wave characteristic you get a file for a single month (eg. nww3.hs.200905.grb, for significant wave height values for May 2009).

This implies that for a 12 years series I have for each location to convert 144 files from grib to txt or dat. As I need also to get peak directions and peak periods this would mean that 432 files need to be converted. Considering that I have to do it for other 4 locations the total number will rise to 2160 files.

For sure there should be a quicker way of doing it! All suggestions in how to do it will be appreciated.

Look at the attachment picture and observe that there exists a strong analogy to the global map of Earth: The blue areas are relevant to the continents while the red ones correspond to the oceans. Is there a possibility of CMB to be just a microwave reflection of radiation and not the so called cosmic microwave background radiation?

More images for CMB here:

For more arguments see also:

Robitaille P.-M., WMAP: A Radiological Analysis, http://www.ptep-online.com/index_files/2007/PP-08-01.PDF

and other references from Stephen Crothers post in:

The original CMB picture was taken from:

Bennett C.L. et al, First-year Wilkinson Microwave Anisotropy

Probe (WMAP) observations: preliminary maps and basic

results.Astrophys. J. Suppl. Ser., 2003, v. 148(1), 1–27

My modest opinion is that Africa, South America and Australia are visible in all CMB pictures.

What is your opinion about?

Please compare the strengths as well as limitations of these two models. Also the answer should consider the recent advancement as far as possible in both the models.

Most of the field experiments reported use a single array of instruments to measure the surf zone wave and current dynamics. I would like to know if anyone has studied the alongshore variation of the wave and current along a stretch of beach/surf zone.

Concerning the analysis of a three dimensional water wave in the ocean, is there any relation (displayable by the equations) between wave refraction and fluid particle trajectories, or a relation to show the water current refraction?

When running a wave model with these winds I suddenly get large biases in 2007. I did a quick fix by reducing some wave model parameters. This was OK for the wave heights, but the mean period seem to suffer a change, possibly because there is more swells in 2007 and following years... So, hum, my next likely step is to look at wind histograms and possibly to a quantile-quantile correction.