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STUDY OF HYDRODYNAMIC RESISTANCE OF A RAFT COMPOSED OF THE FLAT RAFTING UNITS OF VARIOUS DRAFT

Pavel Perfiliev

Abstract

Large reserves of forest resources (according to UN estimates, the area of forests in the Russian Federation, is 8.5 million km?) have provided a significant development of the forest industry. Together with large investments in the timber industry complex, it became possible to optimize the technological processes, machines and equipment of enterprises. At the same time, it is also necessary to solve the issues of the most rational forest management. Sustainable forest management assumes limiting of the volume of harvesting round timber to a size that provides sustainable forest management. The article suggests the one of the options for solving the problem of sustainable forest management in the Arkhangelsk region of the Russian Federation. The volumes of logging in the region are not rational. Estimated cutting in the Arkhangelsk region, according to various estimates, is slightly more than 23 million m?. At the same time, the volume of harvesting round timber is approximately in 2 times lower than the volume of the cut-off area. This is mainly due to the fact that the development of the forest road network in the region is at a low level and the logging site is located at a considerable distance from the main transport arteries. Due to the fact of the geographical features of the Arkhangelsk region, the logging site becomes inaccessible for year-round harvesting and removal. In recent years, the temperature regime (freezing) necessary for removal starts from January and ends in April, so logging enterprises have a sharp shortage of time to develop export volumes. Expansion of the network of forest roads in the current economic conditions is almost impossible, since the state has laid the burden of their construction and operation on logging companies. This ultimately affects the cost of raw materials for processing companies and their competitiveness. The authors believe that it is necessary to increase the volume of roundwood transportation by natural transport arteries-rivers, which according to some estimates at considerable distances of wood transportation is economically expedient. In this case, the most rational is the method of dense timber rafting. At present, small and medium-sized rivers are practically not used for raft transport, in view of the insufficient dimensions of the timber-logging course. The article presents the results of solving the problem of the limited dimensions of the timber-floating course for the melting of forest-transporting units along small and medium-sized rivers. For these purposes, a design of a raft with different drafts of cohesive units has been proposed. In the paper, the problems of determining the hydrodynamic resistance of the design of the forest transport unit were examined, the mathematical dependences of the resistance coefficients were experimentally determined, and the dependence of the hydrodynamic resistance on the overall dimensions of the forest transport unit was analyzed.

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