Dear all, i am also want to simulate Ground Source Heat Exchange for U-Pipe. On edge of u part (ground and u pipe), i am using unstructured mesh. I am usin ansys fluent 17.2. I find problem in overlap interface in that part. I have made. i try to divide it into small part then make mesh for each part. I also manually make interface. but, this problem is not solved. Do you have any I idea?