In vehicular networks, high mobility and limited transmission range of Road-Side Units (RSU) cause dynamic topological changes and result with interference occurred by transmission of vehicles. Moreover, due to the limited bandwidth of IEEE 802.11p based vehicular communication, providing a fair share of network resources among vehicles is essential for an efficient network management. Therefore, flow and interference management challenges cause a degradation in percentage of flow satisfied by effecting quality of communication and enhancing interference in vehicular networks. These aforementioned two challenges can be mitigated with Software-Defined Networking (SDN) paradigm where a centralized controller can schedule data flows and then coordinate power level of vehicles. Hence, in this paper, the cooperation of SDN and IEEE 802.11p based vehicular communication has been proposed in vehicular networks. We present a novel software-defined flow and power management model implemented into controller. Here, we classify vehicles based on Quality of Experience (QoE) and model RSUs with a queuing theoretic approach. Then the proposed model is used to detect unsatisfactory vehicles and estimate effective and accurate amount of transmission power of these vehicles so that unsatisfactory vehicles will be served a new assigned RSU with optimal signal level. Moreover, we redefine flow label field in OpenFlow flow table so that controller can manage to RSUs by imposing some behaviors. Numerical results show how a better flow satisfied can be maintained by implementing this idea.