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Chapter 5 - Test results
5.5 Tests of Peter (1986)
Though the performed tests cover quite a large number of discharges, longitudinal bed slopes and
different types of wall roughness, many important parameters were kept constant: the radius and
the width of the channel as well as the grain size distribution. To establish a generally applicable
scour formula, the acquired data set had to be extended to determine the influence of these
parameters. Therefore 32 tests performed by PETER (1986) at the “Versuchsanstalt für Wasserbau,
Hydrologie und Glaziologie” (VAW) of the “Eidgenössische Technische Hochschule, Zürich”
(ETHZ) were introduced in the database. This allowed an extension of the data set (45 tests) to 77
tests.
The additional tests cover radii to width ratios of 2 and 3.5 compared to 6 in our tests. Peter performed
his tests with 5 different sediments from almost uniform grain size to wide sediment mixtures
( d m = 0.45 ÷ 5.1 mm, σ = 1.19 ÷ 3.21 ). The Froude numbers ranged from 0.3 to 1.2
(compared to 0.68 to 0.97 in our tests) and the Reynolds numbers from 700 to 4100 (compared to
44’000 to 63’000). Peter performed his tests in a 50 to 80 cm wide channel, with a radius of 1.60
and 1.75 m in a 135° bend (see also § 3.5.2/10) with a rectangular cross-section 1 . The bend was
located between a 2.60 m long inlet reach and a 1.50 long outlet reach. The discharges between 2
and 48 l/s were rather small compared to the tests performed in this study. The results of Peters
tests are given in Appendix 1.4.
1. Peter also performed some tests with a trapezoidal cross-section; but they were not used in the
present study.
page 112 / November 9, 2002
Wall roughness effects on flow and scouring