Notch angle

Calculate the volumetric flow rate in m3/s through a V-notch weir when the height of liquid above the weir is 0.15 m given that the notch angle 6 = 20° and the discharge coefficient Cd - 0.62. 

Cipolleti weir—A trapezoidal weir where the notch angle compensates for the reduction in flow dne to contraction. 

S angle of inclination of channel in siructused packing B notch angle, degrees... 

Typical V-notch angles range from 30 to 60°. Smaller angles allow more drip points to be incorporated, but increase distributor cost and its sensitivity to fabrication irregularities. Often, the bottom apex of the notch is rounded into a y shape or extended into a narrow slot to provide a smaller angle. Methods for sizing notched-trough distributors are discussed elsewhere (111, 228). 

The usual notch angle for impact tests is 45°. This means that the largest possible 9 value is 1.18 rad. By Eq. (9.5) the tensile stress at the tip of the yielded zone could rise to 2.28 times the unrestrained tensile yield stress. The yielded zone would be large at this stage with the point B at a distance 3.25 a from the centre of the notch. In practice, the yielded zone rarely becomes this large because either... 

The presence of notches, sharp angles, voids, particle inclusions, and small inserts tends to concentrate stress on impact. One way of studying the sensitivity of a polymer or polymer compound to stress concentration is to carry out a series of tests with different notch angles or notch tip radii. Materials vary enormously in flieir notch sensitivity, as is shown in Figure 1.46. Materials, such as unplasticized PVC, nylon, polyacetals, and PCs (not shown in the diagram), are very sensitive to... 

Dimension between notch tips Notch angle Radius of notch... 

The notch test according to ISO 13479 is one variation of the creep test and evaluates tear propagation strength in particular. Other than in the constant-stress test, a surface defect is defined by a notch The test pipe is prepared with four horizontal notches offset by 90° (notch angle 60°, notch depth 20% of wall thickness) over its length. The requirement for plastic pipes in this test is a service life of at ieast 165 h at 80°C under a stress of 4.6 N/mm [266],... 

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