Summary of CFD Results

5.1 Animal Representation

The representation of animals within the computer models incorporates the following physical effects: Fluid blockage blockage to the deck air flows by the animal’s presence Energy source from skin Energy source from breath Moisture mass source from skin Moisture mass source from breath Momentum source from breath action at the mouth Geometrically, each animal is represented as a prismatic object located some distance above the deck floor. Key dimensions were chosen to be representative of typical real animals ie. height, length, overall surface area. Using such simplified prismatic bodies enables a more efficient meshing discretisation of the computational domain. One major issue for consideration was the space and proximity of adjacent animals. In most instances meshing would have proved much more difficult, if not impossible, if more curvilinear or ‘organic’ animal geometries had been implemented. Numerous such geometric animal models are positioned on each modular deck tier. Packing orientation and density for the initial runs has been chosen to be representative of typical conditions. Animal breath is simulated by drawing in ambient air at the side of the head, heating it, adding moisture, and then emitting it as a steady continuous air jet from the mouth. Typical thermodynamic data to be used in the modelling of the animals has been collected from numerous sources and rationalised to be self consistent.

5.2 Deck Representation

Each deck tier itself is modelled as a floor and roof only no side rails but includes provision for horizontal supply jets at each end. Roof beams are modelled as 2D blockages projecting down from the ceiling. A half-aisle has also been included to enable repetition of the same deck module across the width of the ship. Periodic boundary conditions used on each deck module will enable taller and wider model assemblies to be readily meshed and run. A variety of detailed ship drawings have been reviewed to determine the generic deck geometry used.

5.3 Summary of CFD Results

Complete details of all CFD results are provided in Appendix C Figure 5.1 below summarises data from all cattle deck CFD runs performed and displays the variation of Effective PAT defined in detail in Appendix C with Mechanical PAT. Curves are drawn for various crosswind strengths. Results from this study have been used to develop the open deck operation guidelines in Section 7.3 of this report and the estimation of minimum required crosswind in the HS software. Figure 5.2 below demonstrates the relationship between Effective PAT and crosswind for the cattle cases modelled where cross wind was included. Project: LIVE.116 – Development of a Heat Stress Risk Management Model Revision F Maunsell Australia Pty Ltd Page 40 of 129 Final Report December 2003 Two 24m closed deck cases were also run; one with a Mechanical PAT of 40mhr and another with a Mechanical PAT of 90mhr to determine the relativity between closed and open deck mechanical PAT. Figure 5.3 and Figure 5.4 similarly summarise the CFD simulations for sheep decks, Figure 5.2 and Figure 5.4 show the correlations adopted for Effective PAT as a function of crosswind for cattle and sheep respectively. Figure 5.1 Summary of CFD Data for Cattle Decks. Variation of Effective PAT with Mechanical PAT 20 40 60 80 100 120 140 160 180 200 20 40 60 80 100 120 140 Mechanical PAT mh Effecti ve PAT m h 0ms XWind Only 24m Deck PAT+0ms XWind 24m Deck PAT+1ms XWind 24m Deck PAT+2ms XWind 24m Deck 0.5ms XWind Only 24m Deck 1ms XWind Only 24m Deck 1.5ms XWind Only 24m Deck 2ms XWind Only 24m Deck x=y 0ms XWind 36m Deck PAT+0ms XWind 36m Deck PAT+1ms XWind 36m Deck 2_8m High 0msXWind 2_8m High 1msXWind+PAT 2_8m High 2msXWind+PAT 3_2m High 0msXWind 3_2m High 1msXWind+PAT Crosswind of 3ms yields Effective PAT of 260 mh Figure 5.2 Variation of Effective PAT with Crosswind for Cattle Decks 50 100 150 200 250 300 0.5 1 1.5 2 2.5 3 3.5 Crosswind ms E ffecti ve P A T m h 2.4m High 24m Deck 2.8m High 24m 3.2m High 24m 36m Deck Correlation 24mDeck Correlation 36mDeck Project: LIVE.116 – Development of a Heat Stress Risk Management Model Revision F Maunsell Australia Pty Ltd Page 41 of 129 Final Report December 2003 Figure 5.3 Summary of CFD Data for Sheep Decks. Variation of Effective PAT with Mechanical PAT 20 40 60 80 100 120 140 20 40 60 80 100 120 140 Mechanical PAT mh Ef fect ive PA T m h x=y PAT+1ms XWind 24m Lower PAT+1ms XWind 24m Upper 0ms XWind Only 24m Upper 0.5ms XWind Only 24m Upper 1ms XWind Only 24m Upper 1.5ms XWind Only 24m Upper 2ms XWind Only 24m Upper 3ms XWind Only 24m Upper 0ms XWind + PAT 24m Lower 0ms XWind + PAT 24m Upper ` Figure 5.4 Variation of Effective PAT with Crosswind for Sheep Decks 20 40 60 80 100 120 140 160 180 200 1 2 3 4 5 6 Crosswind ms E ffecti ve P A T m h 24m Deck - Bottom Pen 24m Deck - Top Pen Correlation 24mDeck Correlation 36mDeck Figure 5.5 shows the effect of reingestion on three decks of cattle. Effective PAT is shown as a fraction of mechanical PAT for three successive decks. Project: LIVE.116 – Development of a Heat Stress Risk Management Model Revision F Maunsell Australia Pty Ltd Page 42 of 129 Final Report December 2003 Figure 5.5 Effective PAT Reduction by Reingestion 20 40 60 80 100 120 140 20 40 60 80 100 120 MPAT Ef fect ive PA T Deck 1 Bottom Deck 2 Middle Deck 3 Top

5.4 Deck and Crosswind Scaling