Albert Strickler

Albert Strickler (25 July 1887 – 1 February 1963) was a Swiss mechanical engineer recognized for contributions to our understanding of hydraulic roughness in open channel and pipe flow. Strickler proposed that hydraulic roughness could be characterized as a function of measurable surface roughness and described the concept of relative roughness, the ratio of hydraulic radius to surface roughness. He applied these concepts to the development of a dimensionally homogeneous form of the Manning formula.

Life Albert Strickler was the only child of Albert Strickler Sr. (1853–1936) and Maria Auguste Flentjen (1863–1945) of Wädenswil, Canton of Zürich, Switzerland. He was married twice, the second time as a widower. Neither marriage produced children. The report validated the Gauckler formula and by inference, the Manning formula. Strickler proposed that the Ganguillet-Kutter n-value, used to characterize hydraulic roughness in the Manning formula, could be defined as a function of surface roughness.

Strickler's equation introduces a new empirical coefficient which must be determined experimentally to define n-value. However, unlike n-value, which has units of T/L1/3, has units of length, and at least in theory, is a measurable quantity. A measurable quantity is potentially useful for channel design and stream restoration engineering where the design value of hydraulic roughness may be unknown.

In 1933, Johann Nikuradse published a study of hydraulic roughness in pipes that validated Strickler's observations of the influence of surface roughness in turbulent flows.

Substituting Strickler's equation for n-value and rearranging terms produces a dimensionally homogeneous form of the Manning's formula:

From experimental data, Stickler proposed that the dimensionally homogeneous form of the Manning formula could be quantified as:

where

In civil engineering practice, the Manning formula is more widely used than Stricker's dimensionally homogeneous form of the equation. However, Strickler's observations on the influence of surface roughness and the concept of relative roughness are common features of a variety of formulas used to estimate hydraulic roughness.

Publications Source:

Strickler, A. (1923). “Contributions to the question of velocity formula and the roughness numbers for rivers, channels and pipes.” Mitteilung 16, C. Mutzner, ed., Amt für Wasserwirtschaft, Bern, Switzerland (in German). Strickler, A. (1924). “Drag resistance of propeller boats, and their performance in inland navigation.” Mitteilung 17, Amt für Wasserwirtschaft, Bern, Switzerland (in German). Strickler, A. (1925). “The regulation of Rhine River between Strassburg and Basle.” Schweizerische Techniker-Zeitung, 22(33), 389–394 (in German). Strickler, A. (1926). “Studies on measurement of discharge.” Mitteilung 18, C. Mutzner, ed., Amt für Wasserwirtschaft, Bern, Switzerland (in German). Strickler, A. (1926). “Relation between the Swiss hydropower development and inland navigation.” Werft, Reederei, Hafen, 7(14), 345–346 (in German). Strickler, A. (1930). “The question of the coefficient in Chézy’s formula.” Gesamtbericht der 2. Weltkraftkonferenz, Berlin, 2, 137–152 (in German).