Interest in the aerodynamics of ground vehicles has been revived onlyrecently. This is due to the explosive increase in the nwnber of ground vehiclesin operation as well as the serious concern about future availability of energyfor massive scale vehicle operation. Vehicle aerodynamics encompasses abroad class of phenomena which result from the flow field generated aroundthe vehicle during its motion. This is governed by the vehicle shape, magnitudeand direction of ambient wind, terrain characteristics and mutual interferencewith other vehicles, etc. Apart from the external flow field, there are two othertypes of internal flows; engine cooling and passenger compartment airconditioning.This work is limited to the external flow around road vehicles andFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.4-1 ConclusionsFrom the experimental results presented and discussed in the previous chapter, the following conclusions may be made :1- The heat transfer characteristics of tubes in fixed volume , bothfor staggered and in-line arrangements are better than those forsingle tube at the same conditions .2- Staggered arrangements of tubes in fixed volume gives better heat transfer coefficient compared with in line one and at the same conditions .3- The optimal tube spacing for different arrangements at is Sh /d and S/d = 1 at S/d = 1 , for both in-line and staggered arrangements.4- A correlation for in-line and staggered arrangements of the present data are developed. This correlation satisfactorily expresses the influences of Re, Pr, and cylinder spacing on the Nusselt Number Nu . The correlation can be used to predict the heat transfer coefficient with reasonable accuracy not exceeding ± 30% of measured values.4-2 Recommendations For Future WorkFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.4-1 ConclusionsFrom the experimental results presented and discussed in the previous chapter, the following conclusions may be made :1- The heat transfer characteristics of tubes in fixed volume , bothfor staggered and in-line arrangements are better than those forsingle tube at the same conditions .2- Staggered arrangements of tubes in fixed volume gives better heat transfer coefficient compared with in line one and at the same conditions .3- The optimal tube spacing for different arrangements at is Sh /d and S/d = 1 at S/d = 1 , for both in-line and staggered arrangements.4- A correlation for in-line and staggered arrangements of the present data are developed. This correlation satisfactorily expresses the influences of Re, Pr, and cylinder spacing on the Nusselt Number Nu . The correlation can be used to predict the heat transfer coefficient with reasonable accuracy not exceeding ± 30% of measured values.4-2 Recommendations For Future WorkFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.4-1 ConclusionsFrom the experimental results presented and discussed in the previous chapter, the following conclusions may be made :1- The heat transfer characteristics of tubes in fixed volume , bothfor staggered and in-line arrangements are better than those forsingle tube at the same conditions .2- Staggered arrangements of tubes in fixed volume gives better heat transfer coefficient compared with in line one and at the same conditions .3- The optimal tube spacing for different arrangements at is Sh /d and S/d = 1 at S/d = 1 , for both in-line and staggered arrangements.4- A correlation for in-line and staggered arrangements of the present data are developed. This correlation satisfactorily expresses the influences of Re, Pr, and cylinder spacing on the Nusselt Number Nu . The correlation can be used to predict the heat transfer coefficient with reasonable accuracy not exceeding ± 30% of measured values.4-2 Recommendations For Future WorkFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.4-1 ConclusionsFrom the experimental results presented and discussed in the previous chapter, the following conclusions may be made :1- The heat transfer characteristics of tubes in fixed volume , bothfor staggered and in-line arrangements are better than those forsingle tube at the same conditions .2- Staggered arrangements of tubes in fixed volume gives better heat transfer coefficient compared with in line one and at the same conditions .3- The optimal tube spacing for different arrangements at is Sh /d and S/d = 1 at S/d = 1 , for both in-line and staggered arrangements.4- A correlation for in-line and staggered arrangements of the present data are developed. This correlation satisfactorily expresses the influences of Re, Pr, and cylinder spacing on the Nusselt Number Nu . The correlation can be used to predict the heat transfer coefficient with reasonable accuracy not exceeding ± 30% of measured values.4-2 Recommendations For Future WorkFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.4-1 ConclusionsFrom the experimental results presented and discussed in the previous chapter, the following conclusions may be made :1- The heat transfer characteristics of tubes in fixed volume , bothfor staggered and in-line arrangements are better than those forsingle tube at the same conditions .2- Staggered arrangements of tubes in fixed volume gives better heat transfer coefficient compared with in line one and at the same conditions .3- The optimal tube spacing for different arrangements at is Sh /d and S/d = 1 at S/d = 1 , for both in-line and staggered arrangements.4- A correlation for in-line and staggered arrangements of the present data are developed. This correlation satisfactorily expresses the influences of Re, Pr, and cylinder spacing on the Nusselt Number Nu . The correlation can be used to predict the heat transfer coefficient with reasonable accuracy not exceeding ± 30% of measured values.4-2 Recommendations For Future WorkFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.4-1 ConclusionsFrom the experimental results presented and discussed in the previous chapter, the following conclusions may be made :1- The heat transfer characteristics of tubes in fixed volume , bothfor staggered and in-line arrangements are better than those forsingle tube at the same conditions .2- Staggered arrangements of tubes in fixed volume gives better heat transfer coefficient compared with in line one and at the same conditions .3- The optimal tube spacing for different arrangements at is Sh /d and S/d = 1 at S/d = 1 , for both in-line and staggered arrangements.4- A correlation for in-line and staggered arrangements of the present data are developed. This correlation satisfactorily expresses the influences of Re, Pr, and cylinder spacing on the Nusselt Number Nu . The correlation can be used to predict the heat transfer coefficient with reasonable accuracy not exceeding ± 30% of measured values.4-2 Recommendations For Future WorkFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.4-1 ConclusionsFrom the experimental results presented and discussed in the previous chapter, the following conclusions may be made :1- The heat transfer characteristics of tubes in fixed volume , bothfor staggered and in-line arrangements are better than those forsingle tube at the same conditions .2- Staggered arrangements of tubes in fixed volume gives better heat transfer coefficient compared with in line one and at the same conditions .3- The optimal tube spacing for different arrangements at is Sh /d and S/d = 1 at S/d = 1 , for both in-line and staggered arrangements.4- A correlation for in-line and staggered arrangements of the present data are developed. This correlation satisfactorily expresses the influences of Re, Pr, and cylinder spacing on the Nusselt Number Nu . The correlation can be used to predict the heat transfer coefficient with reasonable accuracy not exceeding ± 30% of measured values.4-2 Recommendations For Future WorkFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.4-1 ConclusionsFrom the experimental results presented and discussed in the previous chapter, the following conclusions may be made :1- The heat transfer characteristics of tubes in fixed volume , bothfor staggered and in-line arrangements are better than those forsingle tube at the same conditions .2- Staggered arrangements of tubes in fixed volume gives better heat transfer coefficient compared with in line one and at the same conditions .3- The optimal tube spacing for different arrangements at is Sh /d and S/d = 1 at S/d = 1 , for both in-line and staggered arrangements.4- A correlation for in-line and staggered arrangements of the present data are developed. This correlation satisfactorily expresses the influences of Re, Pr, and cylinder spacing on the Nusselt Number Nu . The correlation can be used to predict the heat transfer coefficient with reasonable accuracy not exceeding ± 30% of measured values.4-2 Recommendations For Future WorkFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.4-1 ConclusionsFrom the experimental results presented and discussed in the previous chapter, the following conclusions may be made :1- The heat transfer characteristics of tubes in fixed volume , bothfor staggered and in-line arrangements are better than those forsingle tube at the same conditions .2- Staggered arrangements of tubes in fixed volume gives better heat transfer coefficient compared with in line one and at the same conditions .3- The optimal tube spacing for different arrangements at is Sh /d and S/d = 1 at S/d = 1 , for both in-line and staggered arrangements.4- A correlation for in-line and staggered arrangements of the present data are developed. This correlation satisfactorily expresses the influences of Re, Pr, and cylinder spacing on the Nusselt Number Nu . The correlation can be used to predict the heat transfer coefficient with reasonable accuracy not exceeding ± 30% of measured values.4-2 Recommendations For Future WorkFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.4-1 ConclusionsFrom the experimental results presented and discussed in the previous chapter, the following conclusions may be made :1- The heat transfer characteristics of tubes in fixed volume , bothfor staggered and in-line arrangements are better than those forsingle tube at the same conditions .2- Staggered arrangements of tubes in fixed volume gives better heat transfer coefficient compared with in line one and at the same conditions .3- The optimal tube spacing for different arrangements at is Sh /d and S/d = 1 at S/d = 1 , for both in-line and staggered arrangements.4- A correlation for in-line and staggered arrangements of the present data are developed. This correlation satisfactorily expresses the influences of Re, Pr, and cylinder spacing on the Nusselt Number Nu . The correlation can be used to predict the heat transfer coefficient with reasonable accuracy not exceeding ± 30% of measured values.4-2 Recommendations For Future WorkFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.4-1 ConclusionsFrom the experimental results presented and discussed in the previous chapter, the following conclusions may be made :1- The heat transfer characteristics of tubes in fixed volume , bothfor staggered and in-line arrangements are better than those forsingle tube at the same conditions .2- Staggered arrangements of tubes in fixed volume gives better heat transfer coefficient compared with in line one and at the same conditions .3- The optimal tube spacing for different arrangements at is Sh /d and S/d = 1 at S/d = 1 , for both in-line and staggered arrangements.4- A correlation for in-line and staggered arrangements of the present data are developed. This correlation satisfactorily expresses the influences of Re, Pr, and cylinder spacing on the Nusselt Number Nu . The correlation can be used to predict the heat transfer coefficient with reasonable accuracy not exceeding ± 30% of measured values.4-2 Recommendations For Future WorkFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.4-1 ConclusionsFrom the experimental results presented and discussed in the previous chapter, the following conclusions may be made :1- The heat transfer characteristics of tubes in fixed volume , bothfor staggered and in-line arrangements are better than those forsingle tube at the same conditions .2- Staggered arrangements of tubes in fixed volume gives better heat transfer coefficient compared with in line one and at the same conditions .3- The optimal tube spacing for different arrangements at is Sh /d and S/d = 1 at S/d = 1 , for both in-line and staggered arrangements.4- A correlation for in-line and staggered arrangements of the present data are developed. This correlation satisfactorily expresses the influences of Re, Pr, and cylinder spacing on the Nusselt Number Nu . The correlation can be used to predict the heat transfer coefficient with reasonable accuracy not exceeding ± 30% of measured values.4-2 Recommendations For Future WorkFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.4-1 ConclusionsFrom the experimental results presented and discussed in the previous chapter, the following conclusions may be made :1- The heat transfer characteristics of tubes in fixed volume , bothfor staggered and in-line arrangements are better than those forsingle tube at the same conditions .2- Staggered arrangements of tubes in fixed volume gives better heat transfer coefficient compared with in line one and at the same conditions .3- The optimal tube spacing for different arrangements at is Sh /d and S/d = 1 at S/d = 1 , for both in-line and staggered arrangements.4- A correlation for in-line and staggered arrangements of the present data are developed. This correlation satisfactorily expresses the influences of Re, Pr, and cylinder spacing on the Nusselt Number Nu . The correlation can be used to predict the heat transfer coefficient with reasonable accuracy not exceeding ± 30% of measured values.4-2 Recommendations For Future WorkFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.4-1 ConclusionsFrom the experimental results presented and discussed in the previous chapter, the following conclusions may be made :1- The heat transfer characteristics of tubes in fixed volume , bothfor staggered and in-line arrangements are better than those forsingle tube at the same conditions .2- Staggered arrangements of tubes in fixed volume gives better heat transfer coefficient compared with in line one and at the same conditions .3- The optimal tube spacing for different arrangements at is Sh /d and S/d = 1 at S/d = 1 , for both in-line and staggered arrangements.4- A correlation for in-line and staggered arrangements of the present data are developed. This correlation satisfactorily expresses the influences of Re, Pr, and cylinder spacing on the Nusselt Number Nu . The correlation can be used to predict the heat transfer coefficient with reasonable accuracy not exceeding ± 30% of measured values.4-2 Recommendations For Future WorkFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.4-1 ConclusionsFrom the experimental results presented and discussed in the previous chapter, the following conclusions may be made :1- The heat transfer characteristics of tubes in fixed volume , bothfor staggered and in-line arrangements are better than those forsingle tube at the same conditions .2- Staggered arrangements of tubes in fixed volume gives better heat transfer coefficient compared with in line one and at the same conditions .3- The optimal tube spacing for different arrangements at is Sh /d and S/d = 1 at S/d = 1 , for both in-line and staggered arrangements.4- A correlation for in-line and staggered arrangements of the present data are developed. This correlation satisfactorily expresses the influences of Re, Pr, and cylinder spacing on the Nusselt Number Nu . The correlation can be used to predict the heat transfer coefficient with reasonable accuracy not exceeding ± 30% of measured values.4-2 Recommendations For Future WorkFrom the experimental study of heat transfer coefficient of single smooth tube, in-line and staggered arrangements of smooth tubes in a fixed volume , we recommend the following research points for the future work as follows:1- Heat transfer coefficient of the different arrangements with anther Sh/d and S/d for both in-line and staggered arrangements in the different fixed volumes.2- Heat transfer coefficient of enhanced tubes surface at the same conditions for both in-line and staggered arrangements in the same fixed volume.3- Optimum design of tube surface enhancement for both in-line and staggered arrangements .4- Study the effect of using hot and moist air on the heat transfer coefficient of the same different arrangements ( in-line and staggered) in the same fixed values.polynomials are used to fit the sequence of joint displacementsfor each of the N joints. Because of the use of the splinefunctions idea, There are only (n-2) equations to be solved for