## 5 Results and Discussion  
The plot of the tangential force per unit span as a function of the blade segment radius or local radius estimated from the VRT is shown in Figure 4. It is discernible from the plot that the curve rises from a tangential force per unit span of about 50.98 N/m at a radius of about 2.867 m to a maximum of 8.23 kN/m at a radius of about 58.9 m after which it drops to a value of 6.23 kN/m near the tip of the rotor blade. The curve shows an upward concavity for local radii between 2.867 m and 58.89 m and a downward concavity for local radii between 58.9 m and 63 m. It is worth noting that the effects of drag on the tangential or driving force on the rotor blade were not taken into consideration at this stage of the research, an upshot of which is the relatively high values of the tangential force per unit span. The effects of drag shall be considered in a future study, where a comparison shall be made between the VRT and the BEMT. The plot of the normal force per unit span as a function of the local radius estimated from the VRT is shown in Figure 5. It is discernible from the plot that the curve rises from a tangential force per unit span of about 113.56 N/m at a radius of about 2.867 m to a maximum of 969.29 N/m at a radius of about 58.9 m after which it drops to a value of 677.26 N/m near the tip of the rotor blade. The curve shows an upward concavity for local radii between 2.867 m and 58.89 m and a downward concavity for local radii between 58.9 m and 63 m. It is worth noting that the effects of drag on the tangential or driving force on the rotor blade were not taken into consideration at this stage of the research, an upshot of which is the relatively high values of the tangential force per unit span. The effects of drag shall be considered in a future study, where a comparison shall be made between the VRT and the BEMT. The plot of the normal force per unit span as a function of the local radius estimated from the VRT is shown in Figure 5. It is discernible from the plot that the curve rises from a tangential force per unit span of about 113.56 N/m at a radius of about 2.867 m to a maximum of 969.29 N/m at a radius of about 58. 58.9 m and 63 m. It is worth noting that the effects of drag on the normal force on the rotor blade were not taken into consideration at this stage of the research. It is discernible from the curves that the estimated values of the tangential force are relatively higher than those of the normal force. This is because the effects of the angle of attack, the local blade twist angle and the blade pitch angle were not considered in estimating the angle of inclination of the resultant of the tangential and normal forces to the tangential force. Figure 6a depicts the plot of the curves of pressure difference as a function of local radius for the ADT, the RAST and the VRT. The three curves appear to coincide at local radii between 2.867 m and 5.6 m with the RAST curve leaving the rest of the curves and running above them. Despite the apparent coincidence between the ADT and VRT curves for local radii between 2.867 m and 45 m, Figure 6b reveals that both the VRT and ADT curves do not coincide within this range of local radii. Both curves intersect at \(r\cong 43\) m after which the VRT curve is seen to rise above the ADT curve. The apparent coincidence of the curves signifies an agreement between the three theories at these local radii. Suffice it to say that all the three curves have upward concavity, even though the VRT and ADT curves in Figure 6a appear to run parallel to the horizontal axis. This apparent flatness of the ADT and VRT curves is the result of the fact that the RAST values are higher than those of the other two theories. The ADT curve appears to be flat in Figure 6b because the pressure difference values for respective local radii are nearly equal.