.. _weuq-0019: Computing Wind Loads on Building Components and Cladding ========================================================== +----------------+-------------------------+ | Problem files | :weuq-0019:`/` | +----------------+-------------------------+ This examples demonstrated a workflow for evaluating component and cladding loads on buildings. The geometry of the building used for this study is a gable roof low rise building taken from Tokyo Polytechnic University (TPU) aerodynamic database. :numref:`fig-we19-1` shows the study building in the CFD model. The STL geometry of the building can be found :github:`here ` that can be imported to the workflow. Most of the input parameters used in this example are similar to the example in :numref:`weuq-0015`. .. _fig-we19-1: .. figure:: figures/we19_study_building.svg :align: center :width: 50% Study building with definition of the components. In this example, the simulation is conducted in model-scale. The geometric and flow properties are given in :numref:`tbl-we19-1`. Please refer to the detailed CFD-based workflow in :ref:`workflow-section`. .. _tbl-we19-1: .. table:: Import parameters needed for the wind load calculation :align: center +---------------------+----------------------------------------------+------------------+---------------+ |Parameter |Description |Value | Unit | +=====================+==============================================+==================+===============+ |:math:`B` |Building width | 24.0 | m | +---------------------+----------------------------------------------+------------------+---------------+ |:math:`D` |Building depth | 16.0 | m | +---------------------+----------------------------------------------+------------------+---------------+ |:math:`H` |Building eave height | 8.0 | m | +---------------------+----------------------------------------------+------------------+---------------+ |:math:`\lambda_L` |Geometric scale | 1:100 | | +---------------------+----------------------------------------------+------------------+---------------+ |:math:`\lambda_V` |Velocity scale | 1:3.0 | | +---------------------+----------------------------------------------+------------------+---------------+ |:math:`\lambda_T` |Time scale | 1:33.33 | | +---------------------+----------------------------------------------+------------------+---------------+ |:math:`H_{ref}` |Reference height (mean roof height) | 8.8 | m/s | +---------------------+----------------------------------------------+------------------+---------------+ |:math:`U_H` |Reference mean wind speed (model-scale) | 7.14822 | m/s | +---------------------+----------------------------------------------+------------------+---------------+ |:math:`T` |Duration of the simulation (model-scale) | 19.0 | s | +---------------------+----------------------------------------------+------------------+---------------+ |:math:`\theta` |Wind direction | 90.0 |degrees | +---------------------+----------------------------------------------+------------------+---------------+ |:math:`z_0` |Aerodynamic roughness length in (full-scale) | 0.30 | m | +---------------------+----------------------------------------------+------------------+---------------+ |:math:`\rho_{air}` |Air density | 1.225 | kg/m^3 | +---------------------+----------------------------------------------+------------------+---------------+ |:math:`\nu_{air}` |Kinematic viscosity of air | :math:`1.5e^{-5}`| m^2/s | +---------------------+----------------------------------------------+------------------+---------------+ |:math:`f_{s}` |Sampling frequency (rate) | 500 | Hz | +---------------------+----------------------------------------------+------------------+---------------+ The upwind condition chosen for this example is open exposure type with aerodynamic roughness length of :math:`z_0 = 0.3` m for wind direction :math:`\theta = 90^o`. To represent the effect of the upcoming terrain a turbulent inflow boundary condition is adopted at the inlet. .. _workflow-section: Workflow ^^^^^^^^^^^^ The input to the whole workflow can be found in a JSON file :github:`here ` In this example, the overall workflow is demonstrated by introducing uncertainty in the design wind speed. The user needs to go through the following procedure to define the Uncertainty Quantification (UQ) technique, building information, structural properties, and CFD model parameters. .. note:: This example can be directly loaded from the menu bar at the top of the screen by clicking "Examples"-"E10: Computing Wind Loads on Building Components and Cladding". UQ Method """"""""""" Specify the details of uncertainty analysis in the **UQ** panel. This example uses forward uncertainty propagation. Select "Forward Propagation" for UQ Method and specify "Dakota" for the UQ Engine driver. For specific UQ algorithms, use Latin Hypercube ("LHC"). Change the number of samples to 500 and set the seed to 101. .. figure:: figures/we19_UQ_panel.svg :align: center :alt: Image showing error in description :width: 80% :figclass: align-center Selection of the Uncertainty Quantification Technique General Information """"""""""""""""""" Next, in the **GI** panel, specify the properties of the building and the unit system. For the **# Stories** use 2 assuming a floor height of approximately 4.0 m. Set the **Height**, **Width** and **Depth** to 8.8, 24.0 and 16.0 with a **Plan Area** of 384.0. Define the units for **Force** and **Length** as "Newtons" and "Meters", respectively. .. figure:: figures/we19_GI_panel.svg :align: center :alt: Image showing error in description :width: 75% Set the building properties in **GI** panel Structural Properties """"""""""""""""""""" Please leave the **SIM** panel of the workflow as it is, this example does not involve any structural analysis. CFD Model """"""""""""""""""" To set up the CFD model, in the **EVT** panel, select "CFD - Wind Loads on Isolated Building" for **Load Generator**. Detailed documentation on how to define the CFD model can be found in :ref:`the user manual`. 1. Specify the path to the case directory in *Start* tab, by clicking **Browse** button. Use version 10 for **Version of OpenFOAM Distribution**. .. figure:: figures/we19_EVT_Start_tab.svg :align: center :alt: Image showing error in description :width: 75% Setting up the case directory and OpenFOAM version in the *Start* tab 2. In the *Geometry* tab, first set the **Input Dimension Normalization** to *Relative* to put the size of the domain relative to the building height. For **Geometric Scale** of the CFD model use 100.0 as the simulation is conducted at model scale. Set the **Shape Type** to *Complex* and import the building geometry by clicking **Import STL** from :github:`here `. Set the **Wind Direction** to 90.0 to simulate wind incidence normal to the building width. See :numref:`fig-we19-geometry-tab` for the details. .. _fig-we19-geometry-tab: .. figure:: figures/we19_EVT_Geometry_tab.svg :align: center :width: 95% Defining the domain dimensions and the building geometry. 2. Define the computational in *Mesh* tab with *Background Mesh*, *Regional Refinements*, *Surface Refinements*, *Edge Refinements* and *Edge Refinements* as shown bellow. .. figure:: figures/we19_EVT_Mesh_tab.svg :align: center :width: 75% Define the computational grid in the *Mesh* tab .. figure:: figures/we19_EVT_Mesh_RegionalRefinement_tab.svg :align: center :width: 75% Create regional refinements .. figure:: figures/we19_EVT_Mesh_SurfaceRefinement_tab.svg :align: center :width: 75% Create surface refinements .. figure:: figures/we19_EVT_Mesh_EdgeRefinement_tab.svg :align: center :width: 75% Apply further refinements along the building edges **Run Mesh** To generate the computational grid with all the refinements applied, click the **Run Final Mesh** button in the *Mesh* tab. Once meshing is done, in the side window, the model will be updated automatically displaying the generated grid. .. figure:: figures/we19_EVT_Mesh_View.svg :align: center :width: 85% Breakout View of the Mesh 4. To define initial and boundary conditions, select *Boundary Conditions* tab. * Based on the values given in :numref:`tbl-we19-1`, set the boundary conditions as shown in the following figure. Here the **Wind Speed Scaling Factor** is defined as a random variable and the uncertainties will be propagated in the wind load calculation. At the **Inlet** of the domain use *TInf* with the specified inflow generation method (DFM). Then, select *Table* for the **Wind Profile** and import the wind characteristics from :github:`here ` .. figure:: figures/we19_EVT_BoundaryConditions.svg :align: center :width: 75% Setup the *Boundary Conditions* 5. Specify turbulence modeling, solver type, duration and time step options in the *Numerical Setup* tab as shown bellow. .. _fig-we19-CFD-num-setup: .. figure:: figures/we19_EVT_NumericalSetup.svg :align: center :alt: Image showing error in description :width: 75% Edit inputs in the *Numerical Setup* tab 6. Monitor wind loads from the CFD simulation in the *Monitoring* tab. Leave this tab options as shown bellow. .. figure:: figures/we19_EVT_Monitoring.svg :align: center :width: 75% Select the outputs from CFD in the *Monitoring* tab Finite Element Analysis """"""""""""""""""""""""" Please leave this panel to the default values, since no structural analysis is needed. We are mainly interested in evaluating wind loads on components and cladding. Engineering Demand Parameter """"""""""""""""""""""""""""" Next, specify Engineering Demand Parameters(EDPs) in the **EDP** panel. Select *Component and Cladding EDP* option which allows the user to define the geometry of components. In the current workflow this is done using JSON file, which is provided in :github:`here `. .. figure:: figures/we19_EDP_panel.svg :align: center :width: 75% Select the EDPs to measure Once specifying the path to this file in **Component Geometry JSON Path**, click **Map Component Geometry onto Building Surface**. This will map the comonent geometries on to the building surface as shown in the following figure. .. figure:: figures/we19_EDP_panel_components.svg :align: center :width: 75% Map components to the building geometry. Random Variables """"""""""""""""" Since the wind speed scaling factor is defined as a random variable, it will show up this panel. Now for the radom variable **wsF** set *Normal* for its probability **Distribution** with :math:`1.0` **Mean** value and :math:`0.2` **Standard Dev**. .. figure:: figures/we19_RV_panel.svg :align: center :alt: Image showing error in description :width: 75% Define the Random Variable (RV) Running the Simulation """"""""""""""""""""""" The CFD simulation for this example is already run, and results are collected. The users can run the remain part of the workflow locally by clicking **RUN** button. Results """"""""" Once the example is run, the results will aromatically show up . Then, the results will be displayed in the **RES** tab. The responses qualitative reported for *Standard* EDP include statistics of floor displacement, acceleration and inter-story drift, e.g., * 1-MP-zone1: represents **mean pressure** on a cladding/component element named **zone1** * 1-RP-zone2: represents **root-mean-square pressure** on a cladding/component element named **zone2** * 1-PP-zone1: represents **peak pressure** on a cladding/component element named **zone1** * 1-MF-dr1: represents **mean force** on a component element named **dr1** * 1-RP-wd1: represents **root-mean-square force** on a component element named **wd1** * 1-PF-wd1: represents **peak force** on a component element named **wd1** The *Summary* tab of the panel shows the four statistical moments of the EDPs which include *Mean*, *StdDev*, *Skewness* and *Kurtosis*. .. figure:: figures/we19_RES_Summary.svg :align: center :width: 75% Summary of the recorded EDPs in **RES** panel By switching to the *Data Values* tab, the user can also visualize all the realizations of the simulation. The figure below shows the variation of the peak pressure variation with the wind speed used in the simulation. .. figure:: figures/we19_RES_DataValues.svg :align: center :width: 75% :figclass: align-center (scatter-plot) Peak pressure vs wind speed, (table) Report of EDPs for all realizations .. [Franke2007] Franke, J., Hellsten, A., Schlünzen, K.H. and Carissimo, B., 2007. COST Action 732: Best practice guideline for the CFD simulation of flows in the urban environment.