N.O. Jensen (1983) presents a simple model for the wake behind a wind generator, comparing it with experimental results. The model assumes the wake is a turbulent wake or negative jet, with the radius proportional to downwind distance. Using momentum balance, the model predicts the velocity in the wake. The model is then extended to handle multiple generators, both in a circular and linear arrangement. The model is tested against experimental data, showing good agreement with measurements. The model accounts for cross-wind variation by incorporating a cosine-bell function, which improves the fit with real data. The model is applied to calculate the output of 10 generators in a circular array and a linear array. For the circular array, the output is reduced due to wake interactions, with an average reduction of about 17%. For the linear array, the output depends on the distance between generators, with larger distances leading to less reduction. The model also considers the effect of wind direction and shows that the average output is not significantly affected by the distance between generators. The results indicate that the circular array has a lower average output than the linear array, but the difference is small. The model is used to estimate the energy production of wind generators in different configurations, highlighting the importance of considering wake interactions in wind farm design.N.O. Jensen (1983) presents a simple model for the wake behind a wind generator, comparing it with experimental results. The model assumes the wake is a turbulent wake or negative jet, with the radius proportional to downwind distance. Using momentum balance, the model predicts the velocity in the wake. The model is then extended to handle multiple generators, both in a circular and linear arrangement. The model is tested against experimental data, showing good agreement with measurements. The model accounts for cross-wind variation by incorporating a cosine-bell function, which improves the fit with real data. The model is applied to calculate the output of 10 generators in a circular array and a linear array. For the circular array, the output is reduced due to wake interactions, with an average reduction of about 17%. For the linear array, the output depends on the distance between generators, with larger distances leading to less reduction. The model also considers the effect of wind direction and shows that the average output is not significantly affected by the distance between generators. The results indicate that the circular array has a lower average output than the linear array, but the difference is small. The model is used to estimate the energy production of wind generators in different configurations, highlighting the importance of considering wake interactions in wind farm design.