A pilot plant of a solar chimney was tested for about 7 months in a suburban area near Naples (Italy) from February to August 2020. The solar chimney is 5 m high with a square-shaped collector of 4.5 m length on each side. In this paper we report and analyse data with the aim to study the fluid dynamic performances. Correlations between air flow and ambient parameters (solar irradiance, temperature, and relative humidity) are studied. A CFD model is developed to simulate the thermal and fluid dynamic behavior of the chimney. Results are useful for a better knowledge of the performances of solar chimneys and their main operating parameters such as air velocity, flow rate, temperature, and residence time that are very useful for the correct design of solar chimneys both as electrical power plants and as atmospheric pollutant abatement plants.