Depth Averaging Results

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There are several ways in which to average 3D TUFLOWFV results over depth in order to visualise or output in a more manageable form. This guide explains the main types.

Depth Averaging Types

BLANK

Sigma

Depth

Height

Elevation

Top

Bottom

Datum

Water Column

Water Surface

Bed Level

Model Datum

Water Surface

Bed Level

Units

Scale

Length Units

Length Units

Length Units

No. Layers

No. Layers


Sigma

Sigma depth averaging averages over the water column between 0 (bed level) and 1 (water surface). This allows for scaled differences between cells and can be used to extract such values as the average of between a quarter and 3 quarters of the water column - Sigma from 0.25 to 0.75

sigma

Depth

Depth depth averaging specifies limits in length units (default meters) downwards from the water surface. This allows a user to pull out results for between 6 12 meters below the water surface - depth from 6 to 12m. The depth will be truncated at the bed level for any cells that may otherwise be exceeded.

depth

Height

Height depth averaging specifies limits in length units (default meters) upwards from the bed level. This allows a user to pull out results for between 6 12 meters above the bed - height from 6 to 12m. The height will be truncated at the water surface for any cells that may otherwise be exceeded.

height

Elevation

Elevation depth averaging specifies limits in length units (default meters) between two values relative to the model's datum (ie. MSL or LAT). This allows a user to pull out results irrespective of water level change such as Between -16 and -10m AMSL - elevation from -16 to -10m. The limits will be truncated at the water surface and at the bed level for any cells that may otherwise be exceeded.

Elevation

Top Layer

Top depth averaging specifies limits in whole numbers of layers (from the model) from the top layer down. Single layers need the upper and lower limits to be the same. This allows a user to pull out results for the top layer - top layer from 1 to 1. The significance of this will depend on the type and combination of layers within the TUFLOWFV model. These limits will be truncated to the maximum number of layers in a cell for any cells that may otherwise be exceeded.

Top

Bottom Layer

Bottom depth averaging specifies limits in whole numbers of layers (from the model) from the bottom layer upwards. This allows a user to pull out results for the average of between the second and fourth layers above the bed - bottom layer from 2 to 4. As with Top layer depth averaging, the significance will depend on the types and combination of layers within the TUFLOWFV model. These limits will be truncated to the maximum number of layers in a cell for any cells that may otherwise be exceeded.

Bottom

MATLAB Usage

All of these depth averaging types are available when using the TUFLOWFV MATLAB tools. Tools such as fvg_sheet and fvg_sheetvec have the properties ref and range. a ref of 'height' and a range of [4 5], would depth average results between 4 and 5m above the bed level.

TUFLOWFV Output

TUFLOWFV now allows depth averaged .nc and .dat output as well. See the TUFLOWFV Manual for further guidance.