Object Detection Issue with Yolov3 DPU on Avnet Ultra96v2 Board

Encountered insufficient memory issue on Avnet Ultra96v2 Board when I tried to detect for the 2nd iteration. Error message as follows :

 Memory usage for the 1st iteration is: 186364 KB

On the 2nd iteration, encountered either one of the following errors :
[DNNDK_XRT] Alloc BO Failed, size: 0x3ac0000
[DNNDK] Fail to alloc memory for DPU Kernel tf_yolov3: Size: 61599748
Load Xclbin Failed
[DNNDK_XRT] Bitstream download failed

After one iteration, how can I release the memory allocated for DPU Kernel ?
Please advise.