Studio Methodology and Challenges

Sun Shading

Ecotect was employed to simulate sun exposure on surfaces of the existing buildings. However during the design phase, digital simulation tool showed its limitation in generating quick feedback. It would take multiple days to generate results for a piece of intricate design due to limited computer capacity. Any changes made from the feedback would require another equivalent length of time in order to obtain results. Hence, digital simulation was not an efficient design aid, as any design process requires multiple revisions of feedback and alteration. For such practical reasons, time lag caused by running complicated simulation is a high cost in a tight design schedule.

The team overcame this by making physical models and taking interior shots with a simulated light source to get a sense of the atmosphere and shading effect of the envelope designs. This method enables quick feedback as designers are able to amend the design by making quick physical changes, such as repositioning the design, quickly cutting away or adding elements to the models. Models could be done in various ways such as via hand-cut, laser-cut or 3D printing. The 3D printers used were EOS Formiga P100 and Makerbot Replicator 2. Formiga employs the technology of Additive Manufacturing, which builds up components layer by layer in fine powder form, and hence is more precise in terms of its resolution. Makerbot employs fused deposition modelling technology with liquefied polymers, producing a visually rougher yet quicker result. The team assembled the 3D printed components with cardboard components.

Wind

Autodesk Vasari was employed to simulate the wind conditions on site. The results were compared with recordings with hand held wind meter (Figure 77). Results generated by Vasari were different from the firsthand experience at site. One key difference was located in Site 1 where a natural courtyard is formed. Vasari showed little to no wind activities in the courtyard while during site visit, although it was one of the windiest parts of the estate. The team then employed Photoshop to incorporate on-site findings with Vasari results. There are some limitations of measuring wind with the hand held device. The determination of the ‘boundary’ of specific wind speed relied heavily on the decisions and intuition of the surveyor. Unlike computer simulation in which changing prevalent wind direction could be carried out across different monsoon seasons, manual wind recording only allows the survey to be done one day at a time, which means future projection is impossible. The wind result of the day is therefore only a fragmented representation of the site’s wind conditions throughout the entire year.

Rain

There is no existing simulation program that carries out rain analysis and the rain splash effect onto a building. The complexity of this simulation is increased due to different monsoon seasons with volatile, changing wind directions and rain volume. In order to simulate how far rain would splash onto the floor plate of each level of the building, the team could only rely on rule of thumb estimation, where the total depth is half of the opening height. Complication and difficulty arose due to varying angles of wind experienced on each orientation of the elevation. There is opportunity for future research on visual representations of the effect of rain on buildings, as currently no established drawing convention exists.

Sound

The sound on site was manually recorded with a hand-held sound meter. Similar to manual recording of wind speed, the limitation lies in the subjective decision of the surveyor in determining the ‘boundary’ of specific recorded decibels. High degree of reliance to intuition may translate to inability to compare results of one site to another.

Simulations of Studio Projects

by Vijitha Ammini Mammen

Simulations were carried out to assess the environmental performance of the buildings after the students completed their studio projects. These simulations consisted of analysis of mainly wind and solar radiation at a master plan level, and a simulation of solar radiation incident on the building designed by students in Plot-1. The software scSTREAM was adopted for wind simulation, while the solar radiation simulations were performed using DIVA-for-RHINO.

Wind Simulation

scSTREAM is a structured mesh, thermo-fluid analysis software which is used for analysis and visualization of fluid flow and heat transfer. As a structured mesh is composed of cuboids, it approximates tiny details and surface curvatures which do not influence the fluid flow significantly. This makes the software useful for architectural applications.

The first step for setting up the model in scSTREAM is to define the computational domain. Following AIJ (Architectural Institute of Japan) Guidelines for computational domain size and representation of surroundings, the lateral and top extents of the domain were set to more than 5H away from the outer edges of the target building area, where H, the height of the tallest building is 120m. The target area consists of the sites of student projects, i.e. Plots 1 to 5. The site and building massing were modelled using SketchUp, and converted to DXF format for loading the model in scSTREAM preprocessor. Of the roads, only those above ground level were modelled.

In this study, two wind directions were considered: North-East and South-West, which will henceforth be referred to as NE and SW winds respectively. The velocities of NE and SW winds at reference height 15m above ground level were taken as 2.9 and 2.3m/s respectively, as sourced from recommended wind velocity data for CFD simulations published by BCA (Building and Construction Authority).

The standard computational grid size was set to 1m x 1m x 1m, with a geometric ratio of 1.2. Thus, a total of 75,204,192 mesh elements were generated. Following AIJ guidelines, QUICK scheme was chosen as the discretization method because being a 3rd order upwind scheme, it had higher accuracy in prediction of wind behaviour. The steady state convergence criterion was set to 0.00001 instead of the default value (0.0001).

As seen from Figures 76, there is good natural ventilation at pedestrian and higher levels of the building. The arrangement of the buildings ensures that wind circulates to all five plots, and does not create patches of stagnant air.