Boundary Element Method And Its Applications Of Non-Linear Analysis Flow Around Hydrofoils

In the present work, the boundary element method is used with a new numerical algorithm to predict the cavitation around two-dimensional hydrofoils. The main difficulty encountered when predicting the cavitation around the hydrofoil, is the determination of The potential at the leading edge of the hydrofoil. The present algorithm overcomes this difficulty and found the control parameter for various NACA sections. In addition to the previous difficulty, three main parameters and their direct effect on the cavitation are also investigated. The present algorithm was first tested on some existing results and an execllent agreement was obtained, then more computations and results were performed.5.1 ConclusionsBased on the results of the previous chapter, the following points can be stated:(1) The present approach compares very well to the results of others and those of real flow simulations.(2) The proposed treatment of potential function at the inception of cavitation enhanced considerably the performance of the model.(3) Generally, the cavitation height and length are affected by the maximum thickness of the hydrofoil.(4) The shape, height and length of the cavity depends on the cavitation number , angle of attack and free-stream velocity .(5) For all tested sections, the height and length of cavitation increase with angle of attack .(6) For all sections, the cavitation length decreases as increases.(7) Except for NACA16006, the cavity length increases with the free-stream velocity .(8) The values of the control parameter is found within the following ranges, see table (5.1):Table (5.1) The ranges of the control parameter .Control parameter Type of NACA RangeNACA-16006NACA-0012NACA-0015NACA-00255.2 Suggestions for future workCavitation phenomenon is very important and complicated. Many parameters that affect cavitation are studied in the present thesis. Others need more investigation. Thus, points of future work may be stated as:1- Three-dimensional investigations of hydrofoil flow.2- Expanding investigation to unsymmetrical hydrofoil sections.3- Investigating the effect of other parameters on the free-surface of the cavity such as time, depth of water, temperature.4- The viscosity may be also included for real flow solution using other schemes.