The knowledge of wave structure and velocity is of great importance to the prediction of annular two-phase flow phenomena. Given that most existing experimental studies focus on the low liquid flow rate, the goal of this study is to extend the understanding of wave characteristics to high liquid flow rate annular flow, i.e. wispy annular flow. Conductance film thickness probes have been used to measure the film structure of upward annular flow at a high temporal resolution. The inlet superficial gas velocity ranges from 10 m/s to 30 m/s and the range of inlet superficial liquid velocity is from 0.06 m/s to 2 m/s. Important parameters including average film thickness, wave height, base film thickness, wave frequency, wave velocity, and interfacial shear stress are measured and analyzed. Existing models for predicting these parameters are comprehensively reviewed and evaluated using the new data. The evaluation results indicate that although these models are developed for annular flow with low liquid flow rates, some of them can also be used in wispy annular flow with reasonable prediction accuracy, except for wave velocity models. The measured wave velocity in wispy annular flow is significantly higher than that in typical annular flow. A new correlation for wispy annular flow wave velocity is developed based on the new data.