Velocity Amplification Factors (VAF) - [source code]
Compute Velocity Amplification Factors (VAF) and annual wind speed at probes from CFD or ML wind-prediction results and EPW weather data. VAF (the term used in the wind-engineering literature for what Eddy3D historically called "wind factors") is the local wind speed normalized by the reference speed. Method: Kastner & Dogan (2022), Building and Environment 212:108639, doi:10.1016/j.buildenv.2021.108639; Kastner & Dogan (2019), Building Simulation 2019, Rome 621-628, doi:10.26868/25222708.2019.210458.
Input
| Name | Nickname | Description | Type |
|---|---|---|---|
| Boundary Conditions | BC | OutdoorBoundaryConditions object from the ABL or Uniform Flow component. | Generic Data |
| Wind Velocity | U | DataTree {direction}[probe] of velocity vectors from the CFD probe results, OR of scalar wind speeds (m/s) from the Wind Predictor's Values output — either engine feeds the same annual wind field. | Generic Data |
| EPW | Path to the EPW weather file. | Text | |
| Probe Height | Height | Probing/pedestrian height in meters. | Number |
| Interpolate | Interp | How each weather hour's direction is mapped onto the simulated directions — for any number of them. Interpolate blends the two BRACKETING directions by angular proximity; Nearest snaps to the closest simulated direction. A wired boolean from an older document still works: True means Interpolate, False means Nearest. | Text |
| Points | P | Optional probe points in the same order as the Wind Velocity tree's branches. Embedded into the Wind Speed output so downstream components — the Pedestrian Wind Comfort mesh — know where each series lives without extra wiring. | Point |
| Factors | What the Velocity Amplification Factors output carries. Annual (per hour) — the default: {hour}(probes), 8760 branches, each hour's factor resolved from the EPW's wind direction through the Interpolate setting; needs the EPW and is built only while the output is wired (prefer the one-item Annual VAF output into Deconstruct Wind). Spatial (per direction): {direction}(probes), one branch per simulated direction. | Text |
Output
| Name | Nickname | Description | Type |
|---|---|---|---|
| Wind Speed | Wind | Annual wind field object (every point's 8760-hour wind-speed series) for the Pedestrian Wind Comfort component. A single object rather than a data tree, so a few thousand probes stay fast. | Generic Data |
| Velocity Amplification Factors | VAF | Velocity Amplification Factors (VAF) — local wind speed normalized by the reference (undisturbed) speed. Indexing follows the Factors setting: {direction}(probes) per simulated direction (default), or {hour}(probes) across all 8760 weather hours when Factors is set to Annual. | Number |
| Annual VAF | AVAF | The direction-mapped Velocity Amplification Factor at every probe for every weather hour, carried as ONE object (probes × 8760, dimensionless) — wire it into Deconstruct Wind for statistics, a colored mesh and per-hour values. Needs the EPW; empty until it is connected. This is the fast path: the tree output above materializes the same numbers as millions of items on the canvas. | Generic Data |