The ESDU standard also outlines theoretical guidelines for the formulation of mean pressure coefficients (Cp) across a circular cylinder. Figures 13 and. Mean forces, pressure and flow field velocities for circular cylindrical structures: single cylinder with two-dimensional flow, Data Item ESDU Goliger, A.M. Engineering Sciences Data Unit (ESDU International, London). ESDU data item Gartshore, I.S. () The effects of freestream turbulence on the drag of .

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This then leads to the pressure distributionsrepresented by Equations 7. Examples areleg members of lattice structures and off-shore structures, bridge cables and pipe lines. Thereason for this is that while for the laminar boundary layer and the associated pressuredistribution tends to depend only on the cross-flow velocity, when transition to turbulent flow in theboundary layer has occurred the subsequent development and separation of the boundarylayer are adversely affected by the esdk dimensional nature of the turbulent wake flow.

For agiven surface roughness this effect is represented in Equation 3. In some situations a gap may exist between the protrusion and the cylinder surface e. Subjects Cylinders — Aerodynamics.

An experimental investigation 800025 the unsteady pressure forces on a circular cylinder in aturbulent cross flow. In this case, providing the gap width h is not large less than about0.

### IHS ESDU Circular cylindrical structure forces and pressures

For a gap width of less than about 0. At supercritical it maybe assumed fsdu there is no dependence on protrusion shape within the limited applicability of 800025 9. Force and stability measurements on models of submerged pipelines. The following data can be obtained from this data Item. The relation between ka or kp and is not fixed; it depends on the actual roughness shapeand its distribution as illustrated by the values in the Table in Section B3 originally derived for roughplatesB1 and deduced from dataB2 for roughness elements inside pipes.

These data havebeen extrapolated through to values of the cylinder-to-shroud diameter ratio equal to zero given byFigure 6 and unity, when CD0 at subcritical Re will be about 1.

## Line types: Drag & lift data

The name field is required. ESDU Mean forces, pressures, and moments for circular cylindrical structures: This exerts aconsiderable influence on the pressure distribution and increases the flow-induced forces over thosepredicted using simple cross-flow theory. ARC 26,AeronauticalRes. Wind forces on and excitation of a m concrete chimney.

Pressures and forces on a circular cylinder in a cross flow at high Reynolds number. The effect of these spanwise protrusions is twofold. Note 84, April Experimental investigation of the characteristics esru flow about curved circularcylinders.

Drag due to grooves in a flat plate with a turbulent boundary layer, at subsonic and supersonic speeds A For edu or rearward-facing steps typical of overlap joints generated when a metal sheet is rolledinto a cylinder the data38 indicate that CD0 is approximately 15 per cent higher than the values given inFigure 8 for subcritical Reynolds numbers.

Lift and drag measurements on stranded cables. The drag coefficient of finite-aspect-ratio perforated circular cylinders. The maximum CL0 occurs at just supercritical Re giving negative CL0 when there is a maximum edu between the flow separation points on the upperand lower surfaces. Drag measurements at high Reynolds numbers of a circular cylinder wsdu with threehelical strakes. The values given in the Table are an approximate guide andvalues close to obstructions may vary considerably from those given.

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## ESDU 80025

Further guidance on the estimation of pressure distributions on finite-lengthcylinders is given in Reference 1. Aerodynamic forces on a stationary and oscillating cylinder at high Reynolds numbers. Experiments on the flow past a circular cylinder at low Reynolds number.

The experimentaldata indicate that for smooth flow conditions the rapid fall in CD0 with Re occurs at a Reynoldsnumber of between 2 and 3 Typicalexamples are chimney stacks, towers, storage tanks, silos, cables, pipe lines, space vehicles and missiles,and elements of structures such as lattice towers and off-shore structures. The flow pattern development from very low to very high Reynolds numbers, and the general effects ofturbulence and surface roughness, are described in Appendix A for conditions where compressibility effectscan be ignored Mach number less than 0.