A few remarks on penalty and penalty-duality methods in fluid-structure interactions

In fluid-structure interaction problems, many people use a penalty method for positioning the structure inside fluid. This is usually performed by considering that fluid very stiff or/and heavy at place occupied structure. These methods are convenient programming point of view but can lead to ill conditioned operators. drawback in numerical solution methods. particular forces applied surrounding flow not always accurately estimated because parameter -which large number- appears their expressions. We suggest this paper mathematical analysis difficulties encountered and we discuss how penalty-duality D. Bertsekas be an interesting alternative overcome them.