it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY CFD AND VIRTUAL REALITY FOR AIRFLOW VISUALISATION Kjeld Svidt Dept of Building Technology and Structural Engineering Aalborg University

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Contents  Background  Methods  Facilities  Cases  Results and conclusions

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY The IT in Civil Engineering group at dept of Building Technology Professor Per Christiansson (1998) (former KBS- Media Lab, Lund University and the IT Bygg program in Sweden) Assistant Prof. Kjeld Svidt PhD student Yoke-Chin Lai

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY The IT in Civil Engineering group. Research areas and projects Virtual Buildings and Collaboration –’Distributed Virtual Workspace for enhancing Communication within the Construction Industry - DIVERCITY’ (EU IST) –’It in Collaborative Design’ (Danish Centre for Integrated Design, CID) Knowledge Nodes for Knowledge Transfer –(SERFIN, Merkurius, e-learning) Digital Cities and Intelligent Buildings

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY CFD at dept of Building Technology - indoor environmental engineering group  Airflow in and around buildings  Office buildings  Industrial and livestock buildings  Mechanical, natural and hybrid ventilation  Thermal comfort  Air quality  Energy efficiency

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY CFD Model of Incineration Hall, Amagerforbrænding 67 m 50 m 21 m Displacement Ventilation Supply Case C-D Outdoor Air Supply Case E-H

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Comparison between Calculated and Measured Results - Amagerforbrænding Vertical Plane at Incineration Line Fill Temperature 52 o C 46 o C 40 o C 34 o C 28 o C 22 o C 16 o C 10 o C 35 o 43 o 34 o o o 53 o

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Thermal manikins Ref: Erik Bjørn

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Airborne transmission of respiratory disease between pig units located at close range (CEPROS) 1% Ref: Bjarne Bjerg, KVL

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Airborne transmission of respiratory disease between pig units located at close range (CEPROS) 0.2% Ref: Bjarne Bjerg, KVL

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Airborne transmission of respiratory disease between pig units located at close range (CEPROS) 0.1% Ref: Bjarne Bjerg, KVL

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Test of VR in a specific project Research project: “Control of Air Movement in Livestock Buildings”... a joint research project between three Danish research groups:  The Royal Veterinary and Agricultural University, Department of Animal Science & Animal Health, Copenhagen, Denmark  Danish Institute of Agricultural Sciences, Department of Agricultural Engineering, Research Centre Bygholm, Horsens, Denmark  Aalborg University, Department of Building Technology and Structural Engineering, Aalborg, Denmark

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Why livestock buildings  Livestock production an important export industry in Denmark  Increased focus on working environment, indoor air quality, animal welfare  New housing types and production systems  New design tools such as Computational Fluid Dynamics

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY The VR part of the project One-day information seminar for professionals in the ventilation industry and consultants from the agricultural extension service. For this seminar, a few cases reflecting research results as well as problem-cases from the industry were selected to be presented in the Virtual Reality facilities at Aalborg University. Airflow was calculated with the commercial CFD-code Fluent version 5.5. Results were displayed with VU visualisation software ( The results were displayed with active stereo in the panorama as well as the six-sided CAVE.

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY What is Virtual Reality ?  Presentations that take place at the VR-Centre ?  Convincing your senses that something virtual is real  Realistic visualisation of phenomena which are difficult to see in reality (e.g. airflow)

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Virtual Reality may include the following elements:  Stereo viewing (different pictures for right and left eye) Passive (polarized or colour filter) Active (shutter glasses)  A certain degree of immersion Wide screens, power walls Large curved screens CAVE Head mounted displays  Realtime interaction with the model/database Mouse or keyboard Tracking of persons or interaction devices Haptic devices

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY VR facilities at Aalborg University (1) Onyx2 IR2 (will be replaced by PC cluster 2003) Lightwave Matrix-Hub Cave Panorama 3D Auditorium

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY VR facilities at Aalborg University (2) Panorama –Ø 7.1m, 160°, H 3.5m –Mono & aktive stereo –28 persons –Tracking

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY VR facilities at Aalborg University (3) 6-sided CAVE –2.5m x 2.5m x 2.5m –Back projektion –Aktive stereo –1 person with tracking, + a few observers without tracking

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY VR facilities at Aalborg University (4) Portable equipment –2.5m x 3.5m –Portable projector and PC –Passive stereo –30 persons +

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Cases selected for VR presentation in the project 1.3D airflow in a laboratory set-up with an isothermal slot inlet 2.Airflow and CO2-concentrations in a laboratory set-up with 4 wall inlets and “pig simulators” 3.Simulation of displacement ventilation in a room with closed pen partitions 4.Airflow in a similar room with a low momentum ceiling inlet 5.Airflow in a room with a radial inlet device

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Case 1 3D airflow in a laboratory set-up with an isothermal slot inlet Air inlet Air exhaust

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Air velocity at different z-positions during 13 hours (5 min average) m from inlet, 0.2 m below ceiling - the flow changes occasionally between two semi-stable conditions - values seem to be mirrored between z = 0.5 m and z = 4.5 m

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Case 2 Airflow and CO2 concentration in a laboratory set-up with 4 wall inlets and “pig simulators” Air inlet Air exhaust

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Case 3 – 4 Low momentum airflow in a room with closed pen partitions Air inlet Air exhaust

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Case 5 Airflow in a room with a radial inlet device Air inlet Air exhaust

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Methods of flow visualisation The presenter could scale and position the model in the 3D environment He could drag filled contour planes and vector planes arbitrarily through the model In addition he could place or drag seed points for streamlines or animated particle tracks in an intuitive way by moving physically around in the model

it.civil.auc.dk KJELD SVIDT, AALBORG UNIVERSITY Results and Conclusions  The VR facilities proved to be very efficient to visualise the three-dimensional airflow for people with no special background in 3D modelling and fluid motion  Especially the CAVE gave a very persuasive experience of being inside a virtual room with a virtual airflow  It requires some experience to navigate in the models and to scale and position them in a suitable way in relation to the physical surroundings (the audience, the panorama screen, the walls of the CAVE etc.)