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The Galactic transient X-ray binary MAXI~J1836-194 was discovered on 29thAugust 2011. Here we make a detailed study of the spectral and timingproperties of its 2011 outburst using archival data of RXTE ProportionalCounter Array instrument. The evolution of accretion flow dynamics of thesource during the outburst through spectral analysis withChakrabarti-Titarchuk's two-component advective flow (TCAF) solution as a localtable model in XSPEC. We also fitted spectra with combined disk blackbody andpower-law models and compared it with the TCAF model fitted results. The sourceis found to be in hard and hard-intermediate spectral states only during entirephase of this outburst. No soft or soft-intermediate spectral states areobserved. This could be due to the fact that this object belongs to a specialclass of sources (e.g., MAXI~J1659-152, Swift~J1753.5-0127, etc.) that havevery short orbital periods and that companion is profusely mass-losing or thedisk is immersed inside an excretion disk. In these cases, flows in theaccretion disk is primarily dominated by low viscous sub-Keplerian flow and theKeplerian rate is not high enough to initiate softer states. Low-frequencyquasi-periodic oscillations (QPOs) are observed sporadically although as innormal outbursts of transient black holes, monotonic evolutions of QPOfrequency during both rising and declining phases are observed. From the TCAFfits, we find mass of the black hole in the range of $7.5-11~M_\odot$ and fromtime differences between peaks of the Keplerian and sub-Keplerian accretionrates we obtain viscous timescale for this particular outburst $\sim 10$~days.

Accretion flow dynamics of MAXI J1836-194 during its 2011 outburst from TCAF solution