A method and system for evaluating both fluid type and fluid flow downhole by applying thermal energy in a flow of the fluid, and monitoring downstream temperature over time to generate a temperature profile. The type of fluid being evaluated can be determined by comparing the measured temperature profile to profiles over time of known fluids because these profiles depend upon these fluids' thermal diffusivities and flow rates. Further, stratified flow in a deviated wellbore can be analyzed by conducting the fluid evaluation at different radial locations in the flow stream so that the presence of water, liquid hydrocarbons, and gas can be identified. The system can include a pivoting arm that selectively spans the wellbore diameter, and which includes multiple thermal sources, each with corresponding thermal sensor, that are spaced along the arm. A frame can be provided for each of the sources and sensors, which is automatically self-oriented along the direction of fluid flow like a weather vane.