OICC Press International Nano Letters 2228-5326 4 4 (December 2014) 2014 10 07 A brief review on viscosity of nanofluids 10.1007/s40089-014-0126-3 EN Purna Chandra Mishra School of Mechanical Engineering, KIIT University, Bhubaneswar, Odisha, 751024, IN Sayantan Mukherjee School of Mechanical Engineering, KIIT University, Bhubaneswar, Odisha, 751024, IN Santosh Kumar Nayak School of Mechanical Engineering, KIIT University, Bhubaneswar, Odisha, 751024, IN Arabind Panda School of Mechanical Engineering, KIIT University, Bhubaneswar, Odisha, 751024, IN Journal Article 2014 10 07 Abstract Since the past decade, rapid development in nanotechnology has produced several aspects for the scientists and technologists to look into. Nanofluid is one of the incredible outcomes of such advancement. Nanofluids (colloidal suspensions of metallic and nonmetallic nanoparticles in conventional base fluids) are best known for their remarkable change to enhanced heat transfer abilities. Earlier research work has already acutely focused on thermal conductivity of nanofluids. However, viscosity is another important property that needs the same attention due to its very crucial impact on heat transfer. Therefore, viscosity of nanofluids should be thoroughly investigated before use for practical heat transfer applications. In this contribution, a brief review on theoretical models is presented precisely. Furthermore, the effects of nanoparticles’ shape and size, temperature, volume concentration, pH, etc. are organized together and reviewed.