Fans

Recently, there has been an unexpected upswing in the field of fans, attributed to the solution of various fluid dynamics problems. The development has been so rapid that a efficiency of 90% has suddenly been achieved in a compact design. As a result, this previously neglected group of machines has gained significant interest, which is also reflected in the translations of the book into several foreign languages. It seems to be the right time to present the entire field in a concise manner. I have revised much of the content, eliminated the unnecessary, and included numerical results from new experiments for practitioners. Significant expansions have been made in the areas of small blowers and cross-flow fans. The important physical principles have been treated in greater detail.