Khristianovich, Sergei Alekseevich

Born Oct. 27 (Nov. 9), 1908, in St. Petersburg. Soviet scientist in mechanics. Academician in the Academy of Sciences of the USSR (1943; corresponding member, 1939); member of the academy’s presidium (1946–56, 1957–62). Hero of Socialist Labor (1969). Member oftheCPSU since 1949.

Upon graduating from Leningrad State University, Khristianovich joined the staff of the State Hydrologic Institute. He was a staff member at the Central Aerodynamic and Hydrodynamic Institute from 1937 to 1953 and the Institute of Chemical Physics of the Academy of Sciences of the USSR in 1956 and 1957. He served as deputy chairman of the Siberian Division of the Academy of Sciences of the USSR from 1957 to 1961 and was director of the Institute of Theoretical and Applied Mechanics of the Siberian Division of the Academy of Sciences of the USSR from 1957 to 1965. From 1965 to 1972, Khristianovich was associated with the All-Union Scientific Research Institute of Physicotechnical and Electronic Measurements, and in 1972 he took up a position at the Institute of Problems in Mechanics of the Academy of Sciences of the USSR. He was named a professor at the Moscow Physicotechnical Institute in 1947.

Khristianovich’s principal works are on the mechanics of liquids and gases and the mechanics of deformable solids. He developed a method for solving problems of the propagation and reflection of long waves (1938), and he solved the two-dimensional problem of determining stresses in platic media from forces specified along a closed curve (1936). He contributed to the theory of seepage for liquids and gases and to the theory of motion of liquid-and-gas mixtures (1941). Khristianovich investigated the flow of gas past a profile with lift at high subsonic velocities (1940). He set forth the principles of a theory used for the design of gas ejectors (1944) and studied gas flow at transonic and supersonic velocities (1941–47).

Khristianovich supervised the development of the first transonic wind tunnels in the USSR (1944–47). He formulated a theory of hydraulic seam fracturing and contributed to the development of a theory of fractures (1955–57). Khristianovich conducted research on the propagation and reflection of weak shock waves (1955–65) and proposed a theory for the plastic deformation of strain-hardening materials (1972). His research has also dealt with steam-gas turbines and methods of intracycle removal of sulfur from mazut at steam power stations (1960–76).

Khristianovich received the State Prize of the USSR in 1942, 1946, and 1952 and has been awarded six Orders of Lenin, four other orders, and various medals.