Module Waves - Revision history

Davidbrito: /* Algorithms */

2013-12-02T16:13:53Z

‎Algorithms

Davidbrito: /* Algorithms */

2013-12-02T16:12:45Z

‎Algorithms

Davidbrito: /* Effective Fetch */

2012-04-26T15:43:25Z

‎Effective Fetch

Davidbrito: /* Effective Fetch */

2012-04-26T15:41:33Z

‎Effective Fetch

Davidbrito: /* Fetch based */

2012-04-26T15:41:02Z

‎Fetch based

Davidbrito: /* Run Phase */

2012-04-26T15:38:18Z

‎Run Phase

Davidbrito: /* Effective Fetch */

2012-04-26T15:34:39Z

‎Effective Fetch

Davidbrito: /* Effective Fetch */

2012-04-26T15:33:19Z

‎Effective Fetch

Davidbrito: /* Effective Fetch */

2012-04-26T15:32:51Z

‎Effective Fetch

Davidbrito: /* Effective Fetch */

2012-04-26T15:30:34Z

‎Effective Fetch

@@ Line 76: / Line 76: @@
 Fetch distances and average depths in wind direction are computed considering the water points in the simulation domain. This means that if there are areas that during the simulation become uncovered (e.g. forming a temporary tidal flat island), Fetch distances or average depths are not adjusted.
 ====Construction Phase====
@@ Line 121: / Line 125: @@
 If using 8 fetch directions than if wind is in a range of 45º around the main octant angle than that fetch value is used that was weighted using the main directions and two adjacent directions (see Figure 1).
 If using 16 fetch directions than if wind is in a range of 22.5º around the main angle than that fetch value is used that had no weighting (see Figure 2).
 ===Wave orbital velocity and excursion===

@@ Line 121: / Line 121: @@
 If using 8 fetch directions than if wind is in a range of 45º around the main octant angle than that fetch value is used that was weighted using the main directions and two adjacent directions (see Figure 1).
 If using 16 fetch directions than if wind is in a range of 22.5º around the main angle than that fetch value is used that had no weighting (see Figure 2).
 ===Wave orbital velocity and excursion===

@@ Line 92: / Line 92: @@
 In case of weighting (FETCH_DIRECTIONS : 8) for main octants, distances and depths are computed for 8 cardinal directions (the weighing is done using the left to the main direction, direction and right to the main direction) - Figure 1.
-[[Image:Fetch8directions.png|200px|thumb|center|Figure 1 - Example of Fetch (8 directions) for North Wind]]
+[[Image:Fetch8directions.png|200px|thumb|center|Figure 1 - Example of Fetch components used for North Wind (8 directions)]]
 In case of no weighting (FETCH_DIRECTIONS : 16) the computed distances (and optionally average depths) explained above are used without weighting - Figure 2.
-[[Image:Fetch16directions.png|200px|thumb|center|Figure 2 - Example of Fetch (16 directions) for North Wind]]
+[[Image:Fetch16directions.png|200px|thumb|center|Figure 2 - Example of Fetch components used for North Wind (16 directions)]]
 To understand the concept, if there was the option for 4 fetch directions (quadrants) then the weighing would be done using the 2 left to the main direction, direction and 2 right to the main direction) - Figure 3.
-[[Image:Fetch4directions.png|200px|thumb|center|Figure 3 - Example of Fetch (4 directions) for North Wind - this option does not exist, it is shown for illustrating the concept]]
+[[Image:Fetch4directions.png|200px|thumb|center|Figure 3 - Example of Fetch components used for North Wind (4 directions) - this option is not used, it is shown for illustrating the concept]]
 So, for the fetch directions weighting, 3 distances (eq. 6) can be used (the cardinal direction, the angle 22.5º to the right and the angle 2.5º to the left). This is called the effective modified fetch (Fm):

@@ Line 90: / Line 90: @@
 =====Effective Fetch =====
 The above distances and average depths can be used directly for wave calculus or can be weighted over 3 directions to account for what was stated in the beggining, that with small wind variation may significantly change fetch distances (or average depths in wind direction).
-In case of weighting (FETCH_DIRECTIONS : 8) for main octants, distances and depths are computed for 8 cardinal directions (the weighing is done using the left to the main direction, direction and right to the main direction).
+In case of weighting (FETCH_DIRECTIONS : 8) for main octants, distances and depths are computed for 8 cardinal directions (the weighing is done using the left to the main direction, direction and right to the main direction) - Figure 1.
 [[Image:Fetch8directions.png|200px|thumb|center|Figure 1 - Example of Fetch (8 directions) for North Wind]]
-In case of no weighting (FETCH_DIRECTIONS : 16) the computed distances (and optionally average depths) explained above are used without weighting.
+In case of no weighting (FETCH_DIRECTIONS : 16) the computed distances (and optionally average depths) explained above are used without weighting - Figure 2.
 [[Image:Fetch16directions.png|200px|thumb|center|Figure 2 - Example of Fetch (16 directions) for North Wind]]
-To understand the concept, if there was the option for 4 fetch directions (quadrants) then the weighing would be done using the 2 left to the main direction, direction and 2 right to the main direction).
+To understand the concept, if there was the option for 4 fetch directions (quadrants) then the weighing would be done using the 2 left to the main direction, direction and 2 right to the main direction) - Figure 3.
 [[Image:Fetch4directions.png|200px|thumb|center|Figure 3 - Example of Fetch (4 directions) for North Wind - this option does not exist, it is shown for illustrating the concept]]

@@ Line 198: / Line 198: @@
 ===Fetch based ===
-If using the fetch based model, the working scheme of the model is very simple: in the constructing phase of MOHID, the distances to land are calculated for all water cells in the 16 cardinal directions defined by the keyword.
+If using the fetch based model, the working scheme of the model is very simple: in the constructing phase of MOHID, the distances to land are calculated for all water cells in the 16 cardinal directions.
 The distances to land can be computed with two different methods, distinguishing them with the keyword [DISTANCE_TO_LAND_METHOD]. If this keyword equals zero, the distances to land are computed along the grid, incrementing half cell size in each cycle step, until land or end of grid is encountered. If the keyword equals one, distances are computed performing tangents to the points and intersecting them with polygons (Land Areas) segments. The first method can not be used with nested models (if grid ends before directions reaches land).

@@ Line 119: / Line 119: @@
 During the simulation period, in each time step and in each and every cell, depending on wind direction, the fetch distance and optionaly the average depth (both in along wind direction) are selected from the matrixes saved and are used together with wind speed and water depth to calculate the wave height and period. In case of depth computed from local cell depth, than the model uses the water column computed from hydrodynamics.
- Insert image for angles used. if 16 direction for fetch than 22.5º ranges are used, if weihgted 45º.
+If using 8 fetch directions than if wind is in a range of 45º around the main octant angle than that fetch value is used that was weighted using the main directions and two adjacent directions (see Figure 1).
 ===Wave orbital velocity and excursion===

@@ Line 100: / Line 100: @@
 To understand the concept, if there was the option for 4 fetch directions (quadrants) then the weighing would be done using the 2 left to the main direction, direction and 2 right to the main direction).
-[[Image:Fetch4Directions.png|200px|thumb|center|Example of Fetch (4 directions) for North Wind - this option does not exist, it is shown for illustrating the concept]]
+[[Image:Fetch4directions.png|200px|thumb|center|Example of Fetch (4 directions) for North Wind - this option does not exist, it is shown for illustrating the concept]]
 So, for the fetch directions weighting, 3 distances (eq. 6) can be used (the cardinal direction, the angle 22.5º to the right and the angle 2.5º to the left). This is called the effective modified fetch (Fm):

@@ Line 96: / Line 96: @@
 In case of no weighting (FETCH_DIRECTIONS : 16) the computed distances (and optionally average depths) explained above are used without weighting.
-[[Image:Fetch8Directions.png|800px|thumb|center|Example of Fetch (16 directions) for North Wind]]
+[[Image:Fetch16Directions.png|800px|thumb|center|Example of Fetch (16 directions) for North Wind]]
 To understand the concept, if there was the option for 4 fetch directions (quadrants) then the weighing would be done using the 2 left to the main direction, direction and 2 right to the main direction).