Regular Array Of Holes Research Articles

Stokes flow through a thin screen with patterned holes

AbstractThree‐dimensional Stokes flow through a thin screen which has a regular array of holes with two orthogonal axes of symmetry has been studied. The governing equation is simplified by the Roscoe potential and solved by an efficient eigenfunction expansion and collocation method. The resistance is found for circular and square holes in square arrays, and circular and hexagonal holes in triangular arrays.

The effect of void arrays on void linking during ductile fracture

As a physical basis for understanding void linking during ductile microvoid fracture, the contrasting behavior of tensile specimens containing random and regular arrays of holes is examined. The results indicate that specimens containing random arrays are less ductile than their regular-array counterparts. The magnitude of this effect depends on the minimum spacing between holes, hole size, and the strain hardening of the material. The experimental results may be understood in terms of the importance of hole/void distribution on a ductile fracture process which is a consequence of both micro- and macroscale shear instabilities.

Influence on LSI Package Wireability of Via Availability and Wiring Track Accessibility

In this paper, experiments are reported which use automatic global and line-packing wiring routines, supplemented by a restricted maze runner, to evaluate the overall influences of several important physical variables upon the wireability of several logic-circuit package types. The logic circuits are contained in subpackages (e.g., modules carrying chips), which are inserted, using pins, into the carrier package in a regular array of holes otherwise available as vias interconnecting the wiring planes. Over a range of connection counts from several hundred to several thousand, it is found that “overflows” (connections not wired by the program) amounting to as much as 10 or 15% of the wires can be substantially reduced in number by careful design. This can be done by using a sufficient number of programmable vias (greater than one per used pin) and by using a track grid ensuring maximum global track accessibility to all pins, or by a combination of both of these tactics in conjunction with suitable wiring algorithms. Some simple theoretical arguments are given which characterize the design problem in the light of the results.

Heat transfer coefficients for the upstream face of a perforated plate positioned normal to an oncoming flow

Experiments were performed to determine heat transfer coefficients on an upstream-facing surface that is pierced by a regular array of holes. The holes were arranged on equilateral triangular centers, and this regular geometry gives rise to a symmetry pattern whereby each hole is surrounded by a hexagonal region, the boundaries of which are symmetry lines. Within each such hexagonal module, the heat transfer and fluid flow characteristics are identical to those of all the other modules which blanket the surface, so that measurements for a single module yield information for the entire surface. This feature has been employed in the design and execution of the present experiments. Two parameters were varied during the course of the experiments—the hole pitch-to-diameter ratio P D and the per-hole Reynolds number Re. The results were tightly correlated by the relation Nu L ∗ = 0.881 Re 0.476 Pr 1 3 . The characteristic dimension in the Nusselt number is the ratio of the module surface area to the pitch, while the Reynolds number is that for flow through a pipe having a diameter equal to that of the holes in the plate. Flow visualization studies confirmed the existence of the array of hexagonal modules.