<div style="line-height:1.7;color:#000000;font-size:14px;font-family:Arial"><div style="line-height:1.7;color:#000000;font-size:14px;font-family:Arial"><div style="line-height:1.7;color:#000000;font-size:14px;font-family:Arial"><div style="line-height:1.7;color:#000000;font-size:14px;font-family:Arial"><div style="line-height:1.7;color:#000000;font-size:14px;font-family:Arial"><div style="line-height:1.7;color:#000000;font-size:14px;font-family:Arial"><div style="line-height:1.7;color:#000000;font-size:14px;font-family:Arial"><div style="line-height:1.7;color:#000000;font-size:14px;font-family:Arial"><div>Dear friends:<br>     In the projection method for the solution of incompressible flow,  a pressure equation with four neuman bcs need to be solved. </div><div>but the pressure matrix is singular. it gives divergence solution.  how to solve this kind of equations.</div><div><br></div><div>Regards</div></div><br><span title="neteasefooter"><p> </p></span></div><br><br><span title="neteasefooter"><p> </p></span></div><br><br><span title="neteasefooter"><p> </p></span></div><br><br><span title="neteasefooter"><p> </p></span></div><br><br><span title="neteasefooter"><p> </p></span></div></div><br><br><span title="neteasefooter"><p> </p></span></div><br><br><span title="neteasefooter"><p> </p></span>