Expériences nouvelles sur l'écoulement en déversoir
Paris, 1888-1898 - all offprint issues from the Annales des Ponts et Chaussées.
1. pages 393-448 with 3 plates ; 2. pages 9-82 with 4 plates ; 3. pages 445-520 with 4 plates ; 4. pages 249-357 with 5 plates ; 5. pages 645-731 with 3 plates ; and 6. pages 151-264 with 1 plates ; all under original wrappers, entirely uncut. Item #4943
The first apparition of Bazin's weir flow formula - very rare set of 6 offprints
"Henry Bazin (1829-1917) became famous for his 1865 report relating to open channel flow. After having started that experimental campaign with his mentor and friend Henry Darcy (1803-1858) in 1856, he presented a report that shed new light on hydraulic questions such as uniform flow, backwater curves, wall roughness and wave propagation in openchannels. That immense experimental work became known less for the equations proposed but more for the methods employed, the accuracy of data and the concepts tested. Bazin thus added to the fame of French advances of the 19th century by an outstanding contribution towards open channel flow.
As a departmental engineer of Côte d'Or, Bazin headed the Canal de Bourgogne service. In 1886, he was appointed inspecteur géneral of the corps des Ponts et Chaussées, such that he had to move to the headquarters at Paris. Yet, he set up another large research project sponsored by the French government and directed to weir flow, the most economic device for discharge measurement but then comparatively inaccurate. This was particularly attributed to poorly defined conditions for weir set-up and tailwater influence. Bazin, by then the most famous experimenter in hydraulics worldwide, knew of these difficulties, because already Darcy had introduced him to the problems relating to the Dijon water supply project. Later, during the channel experiments, discharge measurement turned out to be again questionable, mainly because water from the navigation canal was used, at bief 57 south of the city of Dijon. However, as also for the canal experiments, Bazin would do much more investigations than previously intended, he not only established a weir flow formula, but also discuss the internal features of weir flow, and set the basis for modern spillway design. He also investigated, together with his pupil and later friend Victor Hégly, the effect of various weir geometries. The final result was six papers published between 1888 and 1898 [the very rare complete set presented here], and a summary published in the 1898 book. From today's point of view, that campaign was extraordinary, given that the observations were made outside in a 2 m wide and 400 m long channel, although Hubert Engels had already established his first hydraulic laboratory at Dresden university in 1892.
[...].
There are in total 6 papers on the weir flow research, all published in the Annales des Ponts et Chaussées, the French corps of Bridges and Roads then the leading professional organization of civil engineering. Bazin's statement that relatively few observations on weir flow were available was incorrect, because that topic was one of the first tackled in hydraulics. [...]
The first account of Bazin's weir research was published in the same issue where Boussinesq had published his results previously referred to Bazin (1887) made the experiments in a channel 2m wide and 200m long on the right side along bief 57 of Canal de Bourgogne. A series of weirs was positioned under identical discharge, to propose a general weir equation. Instrumentation was essentially as for the 1865 campaign. The first step involved thin-plate weirs in a rectangular prismatic channel of various weir heights p. Overflow depths h varied between 0.06 and 0.41 m. The discharge coefficient was expressed as C = M[1 + 0.55(h/(h+p))2] where M=0.425 (±3%) is the basic weir crest coefficient. The second result of that paper was the definition of various nappe types, including the deprimed, the adherent, the undular and the submerged nappes . A commission chaired by Boussinesq awarded that work with Prix Montyon, a success for Bazin.The second paper was directed to the nappe features for free flow over a sharp-crested vertical weir. Bazin thus intended to check the computations previously made by Boussinesq. The figures constructed by Bazin shows a definition sketch, with the gage used for detailed nappe observation, and the reading mechanism and show also the result with the scaling length equal to the overflow depth h. It may be observed that all the data follow a common trend and define curves both for the upper and lower nappes. The lower nappe geometry is essential for concrete spillway crests to avoid cavitation damage, a procedure based entirely on Bazin's findings and introduced around 1940 for the Hoover dam, USA. That study accounted also for sloping weirs of angles between 45° and 155°, with the discharge coefficients essentially in agreement with the approach of Boussinesq. The internal pressure and velocity distributions were determined at the section of the lower nappe maximum. It was demonstrated that the sum of pressure head, velocity head and elevation from an arbitrary datum was 1.006, instead of 1.000 according to the Bernoulli equation. That result sheds light on Bazin's standards.The third and forth papers involved the effect of submergence on weir flow, a feat that had received considerable attention in the past because of its relevance in practice. Bazin realized that free weir flow, for which the nappe neither adhered nor was drawn down, was essential for accurate discharge measurement. He set out limits for free weir flow, plus adequate nappe aeration to create atmospheric pressure below the lower nappe air cavity. The final proposal involved a thin metallic plate mounted on a weir structure with a 45° bevel at the downstream crest side. Today, that crest geometry is a standard, based mainly on these findings. Bazin then investigated the pressure and velocity distributions for submerged weir flow. He proposed a formula for the discharge coefficient that was combined of the free flow features as previously explained, times the submergence effect, in which only the relative elevations of downstream and upstream flow depths were involved. That representation made history, because a number of effects can be described by individual functions, such as in. Bazin's fifth paper was directed to the effect of streamwise weir extension, i.e. broad-crested weirs of various shapes were considered, as used in hydraulic practice when overflow depths are larger than about 0.50 m and a more massive design is required. Bazin thus left the subject discharge measurement and considered practical issues of weir design.The last paper Bazin involved various weir geometries and their discharge behavior. However, Bazin did not further investigate the current ogee weir shape. The so-called standard crest design results for a zero pressure nappe surface as introduced by the American Muller (1908) based on the Bazin data and popularized by Creager (1917).Bazin's weir research has had a fourfold impact: (1) Weir formula, (2) Observational details, (3) Hydraulic similitude, and (4) Combined experimental and computational approach.
The Bazin formula for the coefficient of discharge was in engineering use until about 1950. Bazin measured discharge volumetrically without a channel provided with glass walls. The most important drawback was the definition of the measuring section relative to the weir, an effect fully accounted for only in the 1970s. Also, his structural finish was poorer than modern setups, such that (slightly) different formulas are currently in use. In contrast to most other studies of that time, Bazin explored weir flow in all its details. Besides the discharge-head relation he extended observations to the internal flow features. Although Bazin's problems with the sight all through life, he had learned from Darcy the proper description of physical phenomena. That collaboration also gave access to the best instrumentation, and Bazin even improved the original Pitot-Darcy tube. The nappe profile for a range of weir geometries rendered the basis for the modern spillway design. His plots reveal an enormous amount of details rendering evidence of the great 19th century experimenter. Bazin's name thus remains related to hydraulic experimentation.The third point is the presentation of data. Consider his Figure 4, where the data for a range of discharges are assembled, because the correct scaling length was selected. The second surprise when reading his papers is the attempt to verify the Bernoulli equation, a monument in hydraulics. By carefully measuring both local velocity and pressure, he demonstrated that the Bernoulli concept applies for his data, and indirectly shed light on his experimental accuracy. The forth outstanding achievement was the close collaboration of two individuals. That was new in hydraulic research. It is not clear whether Boussinesq had contacts to Bazin prior to the weir research; he in any case published the first note at a time when the weir research was in progress. It was also Boussinesq that finally convinced his colleagues at Académie des Sciences to award Bazin the scientific honor as a member. (Hager, "Henry Bazin - And weir flow" in Proceedings of the 30th IAHR World Congress (Thessaloniki, 2003), pages 49-54).
An very rare set, entirely uncut and under original wrappers of this landmark on modern hydraulic engineering.
Price: €1,200.00