OICC Press Journal of Theoretical and Applied Physics 2251-7235 7 1 2023 11 17 String cosmological models with bulk viscosity in Nordtvedt’s general scalar-tensor theory of gravitation 10.1186/2251-7235-7-50 EN Uma Maheswara Rao Velagapudi Department of Applied Mathematics, Andhra University Neelima Davuluri Department of Applied Mathematics, Andhra University Journal Article 2023 11 17 AbstractWe have obtained and presented spatially homogeneous Bianchi types II, VIII, and IX string cosmological models with bulk viscosity in Nordtvedt's (Astrophys. J. 161:1059, 1970) general scalar-tensor theory of gravitation with the help of a special case proposed by Schwinger. It is observed that only the bulk viscous cosmological model exists in the case of Bianchi type IX universe. Some important features of the models, thus obtained, have been discussed.