The effect of aspect ratio of end plate separation upon base pressures recorded on a square bar

Toy, N.; Fox, T. A.

doi:10.1007/bf00369118

Cited by 7 publications

(2 citation statements)

References 4 publications

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“…Thus, the spanwise length of the central region of "two-dimensional" flow conditions is seen to be linearly related to the aspect ratio of the cylinder between the end plates. This result is consistent with the findings of Toy and Fox (1986) in the case of similar mean base pressure distributions recorded on a cylinder of square cross-section fitted with end plates at various aspect ratios.…”

Section: Resultssupporting

confidence: 82%

On the use of end plates with circular cylinders

Fox

West

1990

Experiments in Fluids

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237order of magnitude as that of model A. Since buildings in model A have set-backs from the street, the open space between the second and third rows is wider than the corresponding space in model B. It would be presumed that ventilation in lightwells connected to the street space would have higher values in model A than in model B. Velocity measurements prove otherwise, however, as demonstrated in Fig. 3. It is further noticed in Fig. 3 that the velocity in the third row lightwell of model A decays with increasing free stream velocity until it vanishes. This interesting behaviour is attributed to vortices taking place in street spaces (Ghazi 1975).Model C was considered in order to study the effect of side passages. The only difference between models B and C is that the latter has no side passages. Measurements indicate that ventilation in the back space of the first side passage of model B is 12 times that of C. This is explained by the observation that the first side passage faces the wind directly, while the other passages are exposed to vortex flow, whereby they lose their effectiveness. Velocities at other locations in model B, however, are slightly lower than those in C. The indications are that, introduction of side passages significantly improves ventilation conditions in the first back space, whereas it adversely affects ventilation in the remaining rows. ConclusionsComparison between airflow measurements on models A and B, which represent detached and attached buildings, respectively, shows that ventilation in back spaces between rows of buildings in model B is superior to that in the narrow back spaces of model A. On the other hand, high airflow is attained in the side spaces of model A. The side passages of model B considerably improve ventilation conditions in the first back space, while marginally affecting the conditions of rear rows of a group of buildings. Furthermore, the airflow in lightwells of model B is not significantly influenced by the presence of side passages.In conclusion, experimental results suggest that a combination of one frontal attached row with side passages, followed by rows of attached buildings with no side passages would be an arrangement superior to the layouts considered. AcknowledgementsThis work was partly sponsored by Grant AT-5-79 of King Abdulaziz City for Science and Technology (KACST). ReferencesAynsley, R. M.; Melbourne, W.; Vickery, B. J. 1977: Architectural aerodynamics. London: Applied Science Ghazi, M. A. 1975: Experimental investigation of the effect of surface discontinuity on step-backward flow. M.Sc. Thesis, Faculty of Engineering, Cairo University Givoni, B. 1976: Man, climate and architecture. 2nd edn. London: Applied Science Mohsen, M. A.; Olwi, I. A.; Ghazi, M. A. 1987: Aerodynamics and ventilation in buildings: Experimental investigation. Solar Wind Technol. 4, 501-507 Olgyay, V. 1963: Design with climate-bioclimatic approach to architectural regionalism. New Jersey: Prinston Univ. Press Olwi, I. A.; Ghazi, M. A.; Mohsen, M. A. 1988: Wind tunnel sim...

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Section: Resultssupporting

confidence: 82%

On the use of end plates with circular cylinders

Fox

West

1990

Experiments in Fluids

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“…There may be a secondary flow in the vicinity of the dent in the spanwise distribution; therefore, the base pressure along the cylinder axis expresses a little variation. Toy and Fox (1986) experimentally examined the base pressure distribution along a square cylinder axis at the Reynolds number of 1.6×10 4 . The spanwise variation pattern of a square cylinder in the vicinity of the end wall is similar to that in the case of the trip-wire type.…”

Section: Surface Pressure Distributionmentioning

confidence: 99%

Aspect ratio and end wall effects on the surface pressure coefficient of a circular cylinder

Inagaki

Mino

Iwamoto

et al. 2014

JFST

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The effects of end wall conditions and aspect ratios on the surface pressure and the local drag coefficients of a circular cylinder were examined experimentally at a blockage ratio of 3.0% and a Reynolds number of 8000. Both end walls supporting the cylinder were flat plates with different tip conditions on which transitional boundary layers were formed. The ratio of the boundary layer thickness to cylinder diameter at the cylinder position was 0.60 and 0.83, and the aspect ratio was varied from 8 to 32. Regarding the thick wall boundary layer, the base pressure coefficient along the cylinder axis was mostly constant for all aspect ratios, with the exclusion of the end wall vicinity, but rapidly rose as the aspect ratio decreased. In the case of the thin wall boundary layer, the base pressure coefficient was very little constant along the cylinder axis, but the difference for various aspect ratios was relatively small. The local pressure drag coefficient at the mid-span increased in the case of the high aspect ratio and the thin boundary layer.

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The generation of turbulence from displaced cross-members in uniform flow

Fox

Toy

1988

Experiments in Fluids

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The effect of aspect ratio of end plate separation upon base pressures recorded on a square bar

Cited by 7 publications

References 4 publications

On the use of end plates with circular cylinders

On the use of end plates with circular cylinders

Aspect ratio and end wall effects on the surface pressure coefficient of a circular cylinder

The generation of turbulence from displaced cross-members in uniform flow

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